Bra

I think, bra works as an essential support system for our limbs and it must be worn, atleast when one goes out. Vest is also worn for keeping our inner limbs guarded and protected from coming in direct contact with our synthetic clothes.

damn a good question. and this is first time here on this discussion forum that i have read every ones reply to your question just because of the curiosity that what could be the answer to your question but didnt find any logic to it. everyone has replied according to their great thoughts where some thoughts were stuck up with sweating which i also feel could be the reason. but why not then for women, why dont they wear vest along with bra, because bra and vest has no comparison if you see both of them, this question comes to my mind and have no answer to it.

bcaz women hv boobs but men hv chest.

becoz most of them dont need one. infact neither do most women except the really big ones.

men wear vest to keep their shirts free from sweat. i dont think there is any other reason.

My understanding is that the vest is evolved from the doublet, which was worn over a shirt or tunic in medeival times. Vest used be an indicator of status. Working men didn't wear them but the wealthy and ennobled did.

I don't know any men that personally wear a vest. I'd take a guess though and say that it might make them look slimming?