Because their bodies are so heavy they fly at pretty much eye level and bump into you while buzzing very loudly. Mostly at night around here- which is pretty creepy. Or, they fall out of trees on to your head. They are really big.
It's true that every time you hear a bell, an angel gets his wings. But what they don't tell you is, every time you hear a mouse trap snap, an angel gets set on fire.
Jack Handey