St. Patty's day Rant

Okay maybe I'm tottally dumb but I never understood the whole "wearing green or you get pinched" Scheme! and what age is too old to pinch? I mean i'm freakin' 25 years old and people still going around trying to pinch me, I tell them, you pinch me I'll punch you and they usually back off. Maybe I just don't see things like others do but i just never got it even when i was younger, i hardly ever wore green on St. Pattys day and always got pinched.
And whats the deal with Green Beer? Isn't Beer sick looking already being Pee Yellow, now for one day they want to go make it Green. I don't see a point in this but then again, i'm not Irish anyway, even tho. I have an Irish last name (thanks to my ex).