What's something everyone does but nobody admits to?

You already covered a big one.

But, nose picking.

I've never met anyone that didn't, eventually, have a boog that wouldn't blow out. They might not go two knuckles deep or anything, but a dainty pinkie poke happens at some point when there's something stuck.

Now, there's folks that only do it when there's no other option they haven't tried, but our noses have evolved in a way that sometimes we just gotta pull out a blockage or irritant. Our fingers fit well, and have the right texture and surfaces to get the job done.

Ever watched a lot of monkey and ape footage? We aren't the only monkey looking critters that do it. It's common as heck

Well, "wanker" is pretty silly to use as an insult...

Urinating in the shower.

Shitting themselves in public. It doesn't happen often, maybe only a handful of times over your life. But it will happen at some point. You'll be at the urinal, or sat on a barstool, go for a cheeky fart, and feel a warm wetness you haven't felt since you were a baby. Then you run to a bathroom stall, see what you can salvage, and excuse yourself from the situation.

It'll happen to you at some point.

Talks to themselves a lot. Ranting and raving in the car pretending you're on the phone, talking to the air at home about recent events... nobody admits it though!