Why?

Why are people assholes? I just got off the phone with my brother. He called to ask me if I had his wife's key to her Harley...No, why? Because it's gone...somebody stole it! At first I thought it was at my parent's house where she had it sitting out for sale(they live on a busy highway, easy place to sell vehicles). But he said she brought it home(out in bumfuck Indiana) to wash it and it was sitting behind the house. I could see it getting lifted from a high density highway, but not out in the middle of nowhere. Why do people have the need to steal stuff? It wasn't even my bike and I'm ready to go on a manhunt. Some people just need a good ass kickin'!