Why Do Answers Get Disapproved?

Maybe it was the way you phrased it or one of the words you used? I know they did it to me a few weeks ago and I really couldn't work out why either.

...Or maybe the aliens took it and we should be wearing our Tin Foil Hats? Lol

Answers get disapproved for the following reasons
1. If there is a duplicate Answer.
2. If the Question is removed
3. If the matter is abusive

Its a computer that approves or disapproves your answers. I'm not sure why it disapproves most of the answers that it does though.