I stole my friends ear buds.
Did you really do that? Why would you steal your friend's earbuds?
I just didn't feel like buying some myself.
A confession is a good start. You should immediately apologize to your friend and return the ear buds promptly. Stealing from your friends is not acceptable.
Why should I apologize? I just wanted to listen to some good music.
Because those ear bud were not yours to take. You should just come clean to him so he doesn't have to wonder where his earbuds are.