I must know the answer to this as well!
However, I am a Christian whose struggling with faith, so I don't worship because I'm not sure what I believe in. Is that a sin?
P.S. no such thing as a sinless person. When you eat too much, it's a sin (gluttony). When you walk past someone who needs help, you're sinning against a brother or sister. If you can desire things that aren't right without giving it a second thought. SIN!
If you think you're sinless, hate to burst your bubble but you're not. Stop thinking you're better than everyone else, gosh!