Hair probably had an important function at some point in human evolution but now it's mostly cosmetic

As a bald man I can tell you that the hair on your head does A LOT to keep you warm. I have to wear hats all year round except in the hottest part of summer.

And in the hottest day you run higher risk of sunburn as the hair is not there to protect :(
- smh just color your head with a marker. you know, maybe use a black marker and draw some fake hair on there
  
  /s
- That's part of why I prefer spray-on sunscreen.
Also do you bump your head a lot?

I appreciate the usefulness of my eyebrows to divert rain away from my eyes. I do not appreciate my moustache’s water gathering properties when walking in humid environments.

Same with sweat; I used to be in a band and shaved my eyebrows for a bit. Sucked under hot stage lights.
aw man, walking on a humid day, get a free lil drink of rainwater from my mustache every few minutes, it's great
- Oh man I feel like a chump... I've just been using mine to sort soup into "drinkable" and "chewable"
- I guess I’ve been looking at it wrong the whole time! Although, living in the countryside would be preferable for moustache-rainwater

It still are there to protect our scalp and skin from sun burn.

I considered that too. I suppose it could help on top of the head. But how about body hair?
- Body hair is vestigial fur that used to help with thermal regulation (insulation against both hot and cold) when dense enough.
- I have quite thick body hair, especially on my back, there have been times when I have had to wear a shirt that was just in the washing machine, so it was spinn dried, but still damp,!it restes on my back hair and I never felt it against my back skin, works brilliantly in an emergency.
  
  This also means that I have another layer of insulation as soon as I put on a shirt, which is quite handy.
- In some spots, it prevents skin getting sore, when there is friction against other skin or objects.

Funny to suggest its cosmetic function isn't important.

Yeah but why my ear hair started growing in so aggressively?

Habitual lack of earmuffs. Your ears have been cold your whole life, so your body has finally adapted to your negligence.
- Can’t look cool wearing warm clothes at the bus stop. 🤪
Plucked the equivalent of a pube from my ear lobe yesterday... Age has cometh
- My husband says he used to have "a swimmer's body," smooth and hairless. But he's 55 now so...
  
  He's got hair in his chest, belly, back, and shoulders, and it's spreading.
  
  Every few months, I pluck the hairs out of his ears. It used to be just one or two but now it's a couple long thick ones and a few small curly ones from each ear.
  
  About a month ago, I noticed he's also got a couple of long wild strands growing out of the peak of each eyebrow.

It's pretty decent at stopping mosquitoes from getting to your skin, sun burn is lessened, but our technology definitely can overcome that. It just takes a little more effort than existing, like hair does.

Sue Johanson taught me hair is for retaining and spreading your scent to sexual mates.

Why is everyone on Lemmy at least as old as I am?
- Because "works just like email" sounds like a good thing to us.
- Apparently most of Gen Z are fine using centralized, for-profit social media. 😔
- If it's true that younger folks are more tech illiterate then Lemmy would be a non starter for them because it's more complicated to understand and use compared to centralized services.

It helps a lot with your sense of touch, too. Whenever I shave anything it feels numb.

Nails too. Whenever i trim my nails, I feel a loss of sensitivity in my hands or feets. Also, both nails and hair are made up of the same body protein, Keratin.
I’ve never thought about that. Like a cat’s whiskers for humans