A sad fact about Christianity is that the biggest factor repelling outsiders is not the message, or the character of Jesus, or even the cost of discipleship. The biggest repelling factor is the behaviour of those who claim to be Christians. Unsurprisingly, judgmentalism, vindictiveness, selfishness, exclusiveness and self-righteousness are not appealing character traits. Gossip is another big problem, as Paul highlights in the second chapter of his second letter to Timothy:
Try hard to present yourself in a way that is approved by God, a worker with nothing to be embarrassed about, interpreting the message of truth correctly. Stay away from godless gossip, as it leads to greater ungodliness, and the words eat away at you like gangrene.
There is something perversely enjoyable about talking in a negative way about other people when they are not there to defend themselves. It is easy to derive spiteful pleasure from tearing someone else down in order to build yourself up in the eyes of others. But something which tears others down instead of building them up is something which should be shunned by followers of Jesus because, as Paul said, the words will eat away at you like gangrene.