1. You're too busy. You have work to finish, papers to write, sports to play and movies to see. Who has time to squeeze in evangelism with such a busy schedule? Sure, by not sharing our faith we are directly disobeying the command of Christ to "make disciples" but, at the same time, we are eternally forgiven for all of our sins. So why not take advantage of our "get out of jail free" card and just keep doing our own thing? Let Jesus take care of redeeming his own souls. Which leads to the second reason to stop sharing your faith...
2. It's God's job to save souls, not ours. Since God is sovereign (in absolute control) when it comes to salvation then why not let him figure out another way to bring his chosen ones into the clan of Christianity rather than it all being on us? Let's be honest, anyone who can part the Red Sea, raise the dead and provide fish and chips for a stadium sized crowd could rain down 4 Spiritual Laws pamphlets from heaven so that people everywhere could read and believe the gospel. He could hire a fleet of skywriting airplanes to spell out John 3:16 in the air space above every tribe and every nation so everyone could read the gospel on a nice blue background in their own language.
Please don't need to remind me of 1 Thessalonians 2:4 and of the fact that,"we were allowed by God to be put in trust with the gospel." I know the verse well. Sure God gave us the privilege of proclaiming the good news but, if he could put us in trust with this responsibility, he could reassign the job to angels as well. After all the word "angel" means "messenger" in the Greek language. Delivering messages is kind of their thing. Angels don't sleep, are fearless and have more time on their celestial hands than we do. I'm sure they would do a way better job at evangelism than we do anyway.
3. Maybe they won't go to hell after all. With all the buzz in churches about whether or not hell is truly the final destination for all those who, on this side of eternity, reject the message of Jesus, it's enough to make you think the unthinkable. Maybe the almost constant thread and threat of eternal damnation throughout the New Testament is a big joke. Maybe it's like the recording of vicious, barking dogs I used to play in my house growing up. Because I lived in a high crime rate area and was often home alone as an elementary school aged kid, I would crank up the barky bark tunes if I saw thugs ebbing closer to our apartment. The recorded sound of pit bulls fighting usually convinced the would be criminals not to even try to break into our not-worth-breaking-into apartment. Perhaps the threat of hell is the same thing, a divine recording of an empty threat. If this is the case then the teachings of Jesus, John, Jude, Peter and Paul on the subjects of fire and brimstone are all bark and no bite. Why waste time and energy trying to save souls from a hell that, for all intensive purposes, doesn't exist?
*Note to the sarcastically challenged about the 3 reasons stated above: I was joking. We should never be too busy to share our faith. God in his sovereignty chose us as his children to be the tools he uses to redeem people from sin, hopelessness and hell. Evangelism is an urgent privilege. It is a non-negotiable requirement for every believer. So let's get busy sharing our faith for all the right reasons.