What is SIN? That's very simple, sin is anything that's in disobedience with God's word (the written and the spoken), and even sometimes against your own good conscience. However, the CHURCH has often labeled things as sins that simply in of themselves are not. Throughout church history, FALSE DOCTRINES and TEACHINGS have crept into the church to do the devil's work, one of which is to burden the people of God in living righteously by STEALING the freedom, joy, peace, hope, and love (and so much more) that comes through real SALVATION through JESUS CHRIST and the receiving of and living by His Holy Spirit, and ultimately, knowing the Father and coming into the realization of what it means to be a son and daughter of God.
Burdens and anything else that leads us away from the Simplicity of the Gospel (good news) and the previously stated truths, often times come from being too busy in the world OR in religiousness. The SPIRIT of RELIGION is a spirit I believe is a main cause of burdens in the church. It is a cancerous infiltrator to the body of Christ, slowly but surely robbing the body of it's POWER the more it is allowed to stalk about.
The PHARISEES of Jesus' time had this same spirit. They added strict rules and regulations for the people to follow many of which they themselves wouldn't even follow, telling the people it was God's law... but God never wrote it. In fact, the PHARISEES were the ones Jesus had to correct most of the time, publicly defusing their self-righteousness and evil. Even going to great lengths to tick them off and confuse them with what he said and did, even though it was all good things that the Father told Him to do.
Granted some of the things they taught they truly believed was the right thing because it was indeed handed down from their ancestors, however many of these things as well Jesus had to correct them on. For example, Mathew 19:3-12: Jesus is asked by the Pharisees the question of divorce that was allowed by Moses. Jesus' answer is basically that Moses allowed divorce because of the hardness of the people's hearts, but that from the beginning God intended for a man and a woman to marry and become one person, and never wanted divorce to be a part of it.
Oddly enough, many Christians have become MODERN DAY PHARISEES. The only difference is that many of them don't know their Bible like the pharisees of old would have known their Torah. OOOH I've heard of just about everything being a SIN! Playing any kind of instrument, playing certain kinds of instruments, watching TV, going to the movies, playing with cards, smoking, chewing, drinking, wearing certain kinds of clothes or jewelry... just about everything that isn't in the Bible and usually nothing much said about that what's in the Bible.
Now these things can all have good and bad effects, and some of which the Bible may have a word of ADVICE or two concerning, but they aren't SIN. Granted unless God told you specifically not to do it, or to do it and you didn't (careful with that one), but don't push what God told to you onto other people. And keeping in mind that some of these kinds of things, for some people could cause them to ACTUALLY sin. Also keep in mind a sense of balance... too much of one thing... maaaay be bad for you.
God expects His children to be mature with time, to know the solid boundaries of right and wrong according to His written and spoken Word, and our own limitations. It's not our place to name anything a sin unless God says so, and when we know what that is, it's not our place to regulate it among everyone (strangers) or to judge them for it, our mandate as CHRISTIANS is to LOVE them, to listen maturely to God and let Him guard your lips and actions. ESPECIALLY if they aren't Christians, you won't do them any good by being their policeman and judge. A word of advise spoke kindly, a nudge, but your responsibility is to show them the love of God and pray for them.
