Why are many of us shy on mics?

While browsing our raid threads, I've noticed that many of our members have a mic, but are really shy to use it. I myself have never used a mic before, but because I want to raid and I know that raiding needs good communication, I went out and purchased one. Have you had negative experiences over the mic before and do you think these issues will come to Destiny? The one thing that I think is good is that you make your own teams for raids, so the people you will have on mic (if from our group at least) should be polite and respectful at all times. Would this help your shyness at using a mic in game?