Sometimes they're great and sometimes I hate them.
I hate it when I'm riding past a parked car and out of nowhere I hear this "beep" or "beep-beep" as someone across the street locks or unlocks their car. Usually scares the $h!t out of me, because I think a car is behind or beside me and it wasn't there a 1/2 second ago. This usually happens to me a few times a week.