In my childhood, there was little cooler than a t-shirt and matching underwear of my favorite superheroes and star wars characters. Who ever came up with Underoos deserves some kind of award.
I remember having Aquaman, Captain America, Captain Marvel (Shazam), Boba Fett (Boba Fett!), Luke Skywalker (I wore this all the time) and of course Batman and Superman.
I know they made me feel like a super hero.