What is it with underwear?

This is something that has been bothering me for quite some time now. What is it with underwear and designs? I mean, I see a lot of underwear that has really awesome and cute designs but what's the point of putting them there? It's not like you're going out without pants or skirts on right? The whole world wouldn't be able to see that smart "Eat Me" tagline or that pretty flower print anyway. Underwear are worn under clothes, so why not just print those designs on shirts where they can be ever-so-easily seen?

Different colored panties, I can understand. Bras too. Sexy lingerie can be excused since you probably wear those when you're on a special date with your partner and things heat up as the night progresses. But regular, everyday panties?

So do you wear these kinds of panties? Why?