Sometime its hard to tell what is a sin and what isn't and on somethings you won't find a bible verse about what your wondering about. For instance I find it OK for me to have a drink every now and then while others believe it is a sin and you shouldn't do it. So who's right? Well we both are in away. Paul describes it this way in the book of Romans.
Romans 14:11-17 ERV Yes, the Scriptures say, "'As surely as I live,' says the Lord, 'Everyone will bow before me; everyone will say that I am God.'" (12) So each of us will have to explain to God about the things we do. (13) So we should stop judging each other. Let's decide not to do anything that will cause a problem for a brother or sister or hurt their faith. (14) I know that there is no food that is wrong to eat. The Lord Jesus is the one who convinced me of that. But if someone believes that something is wrong, then it is wrong for that person. (15) If you hurt the faith of your brother or sister because of something you eat, you are not really following the way of love. Don't destroy anyone's faith by eating something they think is wrong. Christ died for them. (16) Don't allow what is good for you to become something they say is evil. (17) In God's kingdom, what we eat and drink is not important. Here is what is important: a right way of life, peace, and joy--all from the Holy Spirit.
So if someone I know has received the conviction from God that drinking is wrong and if by drinking around them it causes them to question their faith, then I have sinned by drinking. Not all things that are wrong for one person is wrong for another. There are direct behaviors that are wrong for everyone. Evil is Evil. Lying cheating and stealing will always be wrong. If I watched a lot of TV and God put it in my heart that I am watching too much TV at that time I should stop watching so much TV because it is now a sin for me to do so. Anything that hinders your relationship with God is a sin for you.