You've got burping, farting, nose picking, underwear pulling to name a few. I would have to go with underwear pulling as long as you're not smelling your fingers after you do it.
I fix my junk in public, too. I don't care. Farting not so much. Burping, yeah. I've burped in public. So what.
Got a three year old who does all four simultaneously. One benefit of being a daddy is that you can roast off a nice one and mostly get away with it as long as you pretend to check the kid's diaper.