This has probably been handled better by other blogs, like "Stuff Christians Like" and "The Church of No People," but I thought I would share some ideas of spreading the Gospel that might not have the life changing, come-to-Jesus impact you might think they have. These are all things I have either been told about or personally experienced.
1. Leaving a tract instead of a tip: Whatever message you "think" you are sending, the actual message you send to the person who has been serving you is "I am a cheapskate. Come be a cheapskate like me." Most people do not want to be known as cheapskates or associate with them. Moreover, when you stiff the server, that tract connecting you to Jesus tells him or her that Jesus is a cheapskate, which is a total lie according to Phillipians 4:19 So next time you are tempted to leave your server a tract, make sure you leave him or her at least a 50% tip. That applies double if you have just eaten at a pricey restaurant because if you can afford to eat at a pricey restaurant, you should be able to afford a generous tip.
2. Putting a tract in a kids Halloween bag when you have been chintzy on the candy: Though you really want to be Jesus' light in a dark holiday, you are actually sending kids the same message as the lousy tipper. My goal has always been to give them really good candy, put a Bible verse on it and to be generous in how much candy you give. Not all of my family members have been on the same page, which is why I eventually started buying those M&M cookies bags at Sam's Club instead of many bags of Hershey's Miniatures. There is no way to be a cheapskate with big bags of cookies.
3. Having two male missionaries walk around, bicycle around or drive around at night and approach a single women who is walking her dog or walking with her daughter with offers of assistance: You may think that you look like the "hands and feet of Jesus," but really, you just appear creepy and most women start feeling for their mace, personal alarms or phone when two men approach them at night. Telling them that you are a missionary doesn't really make them feel any safer because anyone can pretend to be a missionary as a ruse to get close enough to do something bad to them. Oh, and don't ask the woman how far of a walk she has to get home. We have read _Little Red Riding Hood_ once or twice in our lives, you know.
4. Standing on a corner or in the middle of a college campus and yelling out to all the people passing buy that they are sinners/prostitutes/drunkards/etc. on their way to hell: First of all some of those people you are insulting just might be Christians. Secondly, you are the exactly the type of person that Jesus would have insulted when he was alive because you try to make yourself appear to be more virtuous than others. Have some humility, please! And maybe it would be better to get to know the people by listening rather than by shouting.
5. Attending a soldier's funeral protesting something that isn't remotely related to nor honoring to the sacrifice that the soldier made for his country or to the grieving family.
To read about a bad missionary idea that (hopefully) hasn't happened yet, read this at Stuff Christians Like. If you have any other examples of bad missions ideas, leave them in the comment section. I am personally trying to stop arguing as my bad missionary idea. Another job for the Holy Spirit!
"But because of his great love for us, God, who is rich in mercy, made us alive with Christ even when we were dead in transgressions--it is by grace you have been saved. And God raised us up with Christ and seated us with him in the heavenly realms in Christ Jesus, in order that in the coming ages he might show the incomparable riches of his grace, expressed in his kindness to us in Christ Jesus. For it is by grace you have been saved, through faith--and this not from yourselves, it is the gift of God--not by works, so that no one can boast. For we are God's workmanship, created in Christ Jesus to do good works, which God prepared in advance for us to do." Ephesians 2:4-9