We always imagine personal defense weapons as a hand held point shoot thingy. If anything was possible what alternatives could you think of?

Some sort of impenetrable energy barrier or whatever that would absorb/reflect whatever fast kinetic blow/projectile would be ideal, IMO. I'd rather have the absorb version so I could just berate them for being violent instead of just getting killed by a bouncing bullet, lol.

An orbital cannon for 1 lb kinetic impactors. You'd probably want them to be in low earth orbit so they can strike quickly. This would of course require a constellation of satellite cannon systems, probably 2000 or so would be sufficient. Also, you'd want to be standing back from your target, probably 20 feet would be safe. Probably.
Also, they'll have mixed results indoors, either putting holes through every floor above you or not quite reaching the target if you were at the base of a skyscraper. Probably not awesome for the skyscraper either...
Maybe someday everyone could have one of these for personal defense.

Omnidirectional body mounted claymore mine.
Just watch your hands.

maybe like a rapid mandatory communication field that makes talking it out feasible in all instances

Anti-tankie mines

A halberd, comparatively easy to use, long range and quite versatile.

Bag of little isopod shaped robots. They are fast moving with nuclear batteries and tungsten carbide shells and lots of sharp edges for chewing and burrowing through flesh. They can also dig into the ground a few inches and hibernate like cicadas to protect an area. Not wireless networked but instead have onboard processing for voice commands, use sense of smell for IFF and echolocation to coordinate their swarming.
Couldn't stop a gun, but they are a deterrent against using it because if you shoot me we both die but you die in a more horrible way.

Yo-yos.

A gun that shoots tiny missiles that aim at the attackers butthole and once they hit they release a jet of freezing water up their butt.
- The first time I ever tried a bidet was right after I installed my own. It was one of those bidets that attaches under the toilet seat. It took me a little while to actually attach it, because my toilet had a really weird connection point and was in the world’s smallest bathroom. But after some struggling (and a lot of swearing) I managed to get it done.
  I plopped down on that thing like it was a porcelain throne, and I was its rightful king. I had been holding it for a while, (due to the aforementioned struggling to attach the bidet to the damned toilet), so the groundhog was already peeking out to look for his shadow by the time I got it attached.
  After doing my business, I confidently grabbed the dial, and cranked that motherfucker up to 11. Up to that point, I believed I was a king… But I sat on a throne of sins. I believed I would simply be greeted with a cool shower. Like Icarus with his wax wings, I was full of hubris. I had flown too close to the sun, and was hurtling towards Poseidon’s icy depths. You’ve heard of Poseidon’s Kiss, where that little droplet of water splashes up and touches your butthole after you pinch one off? Poseidon got all the way to fifth base, in about a quarter of a second… And he didn’t use lube. It instantly blew water so far up my ass I could have brushed my teeth.
  But that’s not all. In my shock, my hand slipped off of the control knob. By the time I managed to find it and turn it back off, I had received what felt like a peppermint colonic. And you know what’s even worse than getting your guts rearranged by an icy fire hose? Feeling it come back out afterwards, and it still being cold. My dear reader, I implore you to take a lesson from my mistake… After installing a bidet, check the water pressure before you use it. It turns out, mine had enough pressure to spray all the way out of the bathroom door, and hit the wall on the opposite side of the bedroom. I had dialed that bitch all the way up to 11, when I only needed like a 2.5…
  All of this to say… I can sympathize.
  
  Sounds like a great way to prepare for anal
- Wait, why would you want to make your attackers horny?
  
  Ummm, adding an optional pepper spray missile if the first one was not effective...

Personal forcefield with a shape of my choosing, activate either by s simple device or algorithmically based on external factors. Great for safety but also handy as an umbrella.

If anything were possible, I have always liked AE van Vogt’s fictional weaponry:
In "The Weapon Shops of Isher", the defensive weapons sold by the shops are advanced ray guns with integrated force fields, making them highly effective against government and criminal threats. These weapons ensure citizens can defend themselves against tyranny and oppression while upholding a policy of non-aggression, aiming to foster a more just government over time.
The weapons can somehow be used to defend but not be used in an act of aggression. And the force field protects the bearer.
A fun read if you are into golden age science fiction.
https://www.prosperosisle.org/spip.php?article974#%3A%7E%3Atext=This+was+one+of+the%2Ccivilization+to+protect+them+against

I've read somewhere and I'm not sure if it's true that there is a device that can be inserted inside the vagina which will essentially bite the rapist's penis and the only way to remove it without destroying the penis is via surgery.
- I believe it's called Rapex.

Laser eyes.
Now you can just look at something you want to destroy without using your arms.
Telekinesis helmets.
Now you can just think about destroying something you can't even see.

DMT clouds making them connect to the universe and lay down 4 minutes
- Fentanyl dart gun
  
  Anti-cop weapon.

We always imagine personal defense weapons as a hand held point shoot thingy.
We do? What is wrong with a baseball bat? Or a sock filled with quarters?
- Both require a lot more effort to stop a threat and can be captured and disarm you at their effective range.
  
  Self defense shootings almost universally happen within arms reach. Nobody is using a sniper for self defense, because you can’t claim you were threatened when they’re too far away. A mugger isn’t going to start mugging you when they’re 50 feet away; They’re going to be in conversation range. A rapist isn’t going to make their intentions known until they already have hands on you.
  Lots of 2A advocates make the mistake of training for a threat that is 50’ away, as if good accuracy at that range is going to help them when an attacker has them by the throat. Instead, they should be training four basic things:
  Fast and repeatable draw. By the time they mentally process that you have a weapon, you should already be firing it. Your draw needs to be drilled the same way you drill reloads or clearing jams.
  Aiming by feel instead of taking time to use sights. Sights are very important at distance, but not so important when the attacker is 5’ away from you. It’s still possible to miss at that distance, but less likely if you’re able to feel where your weapon is pointed. Center mass from 5’ away is a pretty fucking large target. Proprioception is a powerful tool, but learning to use it with a weapon takes a lot of practice.
  Keeping your weapon close, so you’re not sticking your arm all the way out towards the attacker where they can grab your weapon. This goes hand in hand with the second point. Because again, they’re likely already within arms reach of the attacker, and you don’t want to just hand them your weapon before you even start firing. If you need to stick your arms straight out in front of you and get an eye focused on your sights before you start firing, they’ll have grabbed your gun before your first shot.
  Keeping your stance solid so the first shot doesn’t immediately knock you off balance. A lot of people do not instinctively know how to maintain balance.
  But gun owners bitch and moan if you ever bring these points up, because they aren’t actually interested in training for self-defense. That’s just the excuse they give, because “I want to protect myself” is hard to argue against.
  
  If the fight starts when you're already at a close range melee weapons have a very decent chance of coming out on top over firearms. Maybe not the sock but bats and knives definitely.
- Held in hand. Point. "Shoot".

High voltage contact shirt. You touch me, you fry
- also good for making grilled cheese sandwiches

Spontaneous Human Explosion guaranteeing Mutually Assured Self-Defence/Destruction.
Like 2 Kings in a Chess game, you can't be next to each other.
- Opposite of the movie Wedlock

personal satellite with Hatsune Miku licensed voice assistant for targeting and fire control. A few lasers of different frequency, a railgun, maybe some emergency snack pods with little chutes.

Foot held point shoot thing

The best defense is avoidance. To that end, a personal time-travel / prognostication device that could both predict danger and chronoport you back to before danger was imminent would be the ultimate defense, though suppose not strictly a "weapon".
- Put it in front of a group of DND players, or any other table top RPG really.
  They'll weaponize it before the session is over.

Magical aura that reads intentions and zaps people. Diablo 2 paladin auras essentially.😺

Self defense is a fantasy of control. If you want to eliminate threats to yourself rationally, eat more vegetables, take care of your mental health, and drive carefully.
- Ah yes the infallible recipe to never be physically assaulted
  
  the statistical recipe to lengthen your lifespan
- I was more or less trying not to refer to weapons of mass destruction. Not implying self defense is virtuous.

Body odour
- Or that guy from Mystery Men who farts.

Temporary blinding LED flash weapon, stink bombs, vomiting, reciting the Captain Ahab monologue from Moby Dick where he's telling them to split their lungs with blood and thunder and crack their oars and backs.
- Captain Ahab monologue
  This one's kind of cool. What about a voice modulator that makes it seems like your voice is their own internal monologue and you can disarm them by boring them to death or confusing them.

Probably some kind of autonomous thingy. Like, a drone with a Taser or some shit.

This is why I have cannons loaded with grapeshot in every room of my house. Never know when I'll need to remove a thief from existence.
- Safety is all about preparation.

Something that makes me disappear instantly and teleports me to the pub down the street. Cold beer is better than hot fight.
- What if it's a bar fight

A tank full of sharks and gloves that dispense a sticky concentrated chum mixture with each hit. Get a couple good body blows in, knock them into the water, let nature (+/-) take its course.