What can I say?

"What can I say" is something you say when you don't have any other good response to what someone says. Some situations where you can give this answer include:

• When someone says something really good about you, and you agree but you don't want to brag.
• When someone is really angry about something, but you aren't able to fix their problem.
• When someone criticizes you, and you agree that it's true.

You can use it like this:

A: You're such a good singer!

B: Yeah, well, what can I say? It's a gift.

a guilty pleasure

A "guilty pleasure" is something that you like, even though you know it's not good.

You use it like this:

This is one of those bands that I know isn't that good, but they're kind of a guilty pleasure for me.

"Guilty pleasures" can include unhealthy food or entertainment that gets you hooked but isn't very intelligent. However, it wouldn't be common to call something very harmful like smoking or using drugs a "guilty pleasure".