Why Do People Yell At Me From There Cars while I'm walking?

So I Know people like to get attention, but seriously? I get off work and this happens at least once a week (No Joke!). Why do people need to yell the things they do? Today alone I had 2 different cars yell at me separate times. One was full of guys calling my a Slut and wat not ( No i don't know any of the people in any car that yells at me like this) and than saying he was gong to fight me and "**** me up" the next car called me a M.I.L.F I'M NOT EVEN A MOM! and no kids were with me. I do not plan on doing anything about it really. I just wanted to know if anyone on here can tell me wat is the point at yelling at a random person if your in a car and can drive away. I think your a if you can't step out of your car to call someone any name good or bad! For the record i was wearing jeans a white muscle shirt and black skate shoes, my hair was up and i was not wearing make up and was carrying a gym bag full of my work clothes.