某些基督徒的行为很差，让我不想信。
Some Christians behave terribly, which puts me off believing.
简答 Short Answer
基督徒的失败恰恰证明了福音的核心信息：人人都是需要恩典的罪人。你信的是完美的基督，不是不完美的基督徒。
Christians' failures actually prove the gospel's core message: everyone is a sinner in need of grace. You place your faith in the perfect Christ, not in imperfect Christians.
详细解答 Detailed Answer
你的失望完全可以理解。看到自称基督徒的人行为虚伪、自私甚至邪恶，确实令人反感。但请考虑以下几点：
1. 基督教从未宣称基督徒是完美的。 恰恰相反，基督教的出发点就是「所有人都是罪人」（罗马书3:23）。教会不是完人的俱乐部，而是罪人的医院。如果基督徒个个完美无缺，那反而证明福音是不需要的。
2. 区分基督和基督徒。 判断一套医学理论好不好，应该看这个理论本身，而不是看某个不称职的医生。同样，判断基督教的真伪，应该看耶稣基督本人——祂的教导、祂的生命、祂的牺牲——而不是某些不合格的跟随者。
3. 不要让别人的罪阻碍你的救恩。 在最后的审判中，你不会因为别人的行为被审判，只会为自己的选择交账。因为张三是坏基督徒就拒绝基督，就像因为某个医生态度差就拒绝救命的药——受害的是你自己。
4. 也看看信仰的好果子。 历史上和你身边，一定也有生命被基督改变、活出美好见证的基督徒。不要只看最差的，也看看最好的——更重要的是，看基督本身。
5. 虚伪的基督徒恰恰是耶稣最严厉谴责的。 耶稣对法利赛人的批评比对任何人都严厉（马太福音23章）。所以你对虚伪行为的反感，其实和耶稣站在同一边。
Your disappointment is completely understandable. Seeing self-proclaimed Christians act hypocritically, selfishly, or even wickedly is genuinely repulsive. But consider these points:
1. Christianity never claims Christians are perfect. Quite the opposite — Christianity's starting point is 'all have sinned' (Romans 3:23). The church isn't a club for saints but a hospital for sinners. If Christians were all flawless, it would prove the gospel unnecessary.
2. Distinguish between Christ and Christians. You judge a medical theory by the theory itself, not by an incompetent doctor. Similarly, judge Christianity by Jesus Christ Himself — His teaching, His life, His sacrifice — not by some unqualified followers.
3. Don't let others' sin block your salvation. At the final judgment, you won't be judged for others' behavior — only your own choices. Rejecting Christ because of a bad Christian is like refusing life-saving medicine because of a rude doctor — you're the one who suffers.
4. Also see faith's good fruit. Throughout history and around you, there are certainly Christians whose lives have been beautifully transformed by Christ. Don't look only at the worst — look also at the best, and most importantly, look at Christ Himself.
5. Hypocritical Christians are precisely whom Jesus most harshly condemned. Jesus' criticism of the Pharisees was fiercer than toward anyone else (Matthew 23). Your disgust at hypocrisy actually puts you on the same side as Jesus.