Sin is wrong no matter what anybody says about it. Sin is breaking God's law, 1 John 3:4. If God says something is wrong then there is no other way of describing it. People try to categorize sin by speaking of "little sins" and "big sins" but all sin, no matter how trivial it may be, is still sin.
In medicine one of the worst scenarios is to find a germ has infected an injection. One tiny germ can cause severe illness, even death to the recipient. The same is true of any sin.
People try to think there are such things as "victimless crimes." They say, "No one got hurt. We just had some fun, that's all." Every sin hurts somebody. The very act of sinning brings guilt and shame on the sinner. And if the sin is with someone else, then they are affected as well.
Now, Christians need to think of something else as well. Sad as it is, so many Christians ignore doing what they should do each day: pray, read their Bibles, and seek to live for Christ in their actions and witness. Worse yet is when these Christians go out and deliberately do something they know is wrong. Not only do they feel the shame and guilt of their action but they become a poor example for others to follow. A Christian may say, "Well, people shouldn't look at me. They should look at the Lord!" The answer to that is simple - people can't see Jesus. But they can see you! And like it or not, you may be the best example of a Christian that somebody has! You say, "Hey, there are far better Christians than me!" Yes, that may be true, but the people in your life don't know them -- they do know you!
Take time to read Matthew 5:14-16. Be the example God meant you to be.