Sleepyjack

I was just wondering why does everyone normally wear underwear in just day to day life. I appreciate that girls wear a bra in order to hold there breasts up and in place, but otherwise why do you wear underwear?
what is its purpose. i have talked about it with my friends and it only really came down to hygiene, tho any other reasons?
I find the hygiene factor a little overated, as i clean myself throughly and switch clothes regulary anyways.

I guess the main deal is with boxer shorts. They are pretty much he same as not wearing underwear ie commando, cause they're not holding anything in place.
I know underwear is and can be very sexy, but i am talking about its fundamental purpose.
If i am not playing basketball or other sports i would be commando for most of the time, and it is great. The reason i don't wear underwear for common everyday use comes down to sometimes getting "ridden" by it (like a mini-wedgy) and it may be not to healthy for my privates, in that it is sometimes quite hot and tight which isn't good for the testies. Also without undies there is more air flow so it doesn't get as hot and consequently sweat etc is less likely (altho i deodrise myself all over anyways)
The only unfortunate circumstance, arise when you get "excited", although even with underwear it has to take up some space, and that underwear only effects the nature of the buldge.

so it'd be intersting to hear your thoughts on the topic and also what underwear you wear and why, in just normal everyday life.