When Christians evangelize, I think it's important to always remember two things; 1. no matter how much you know, how long you've been saved, how many scriptures you can recite, you are nothing without God and 2. your job is to witness to others about Christ and what the Bible says about how they should live their life not to force it to happen or become angry if it doesn't.
If we all just have the mentality that we are only here to plant seeds of God's perfect love, forgiveness, compassion and mercy and then let Him do the rest there won't be these views of Christians being these overbearing, hipocritic, finger pointing creatures.
"What, after all, is Apollos? And what is Paul? Only servants, through whom you came to believe—as the Lord has assigned to each his task. I planted the seed, Apollos watered it, but God made it grow." 1 Corinthians 3:5-6