Men in Cars

So as I have been walking and riding my bike to work I have noticed something.

About 10% of the male population in cars cat call.
I have come to two conclusions as to why they do it:

#1 They think you are attractive (does anyone anymore to respond to that archaic form of finding a mate?)
#2 They are real dill holes and are looking to hurt you: buy shouting as loud as they can from their cars, causing you to jump, or swerve.

I think I have shown great restraint in not giving them certain hand signals to express how I feel about what they have just done. I could really get hurt, I could trip and fall I could swerve into traffic... Yeah that is really funny...
Also I found it very interesting that EVERY ONE of the cars that has done this has been a truck.