Yes, dude. Totally.
Not being vain or shallow, but I usually attribute it to looks. Personally, I think there is huge inconsistency in how I look. Really good days, I am invincible. Bad days, I want to be invisible.
And of course, when your happy with how you look, your more confident, which makes you more attractive, and so on and so forth. It keeps itself going.
Although my friends day i always look the same - we of course notice differences in how we look that others dont (you see your face every day your entire life - noone knows it better) but wheter its real or imagined is irrelevant! It always has an impact on your confidence.