Why do guys stare at me?

its kind of weird. but i dont get why they stare at me. like i'll go to wall mart an walk past a guy and theyll say hi to me or just stare. but i dont even kno them. im not rude i'll say hi back. (ok im in high school) an sometimes after school i walk. an i ve noticed the people in the vehicals ping by. they stare at me and sometimes even honk. and then this truck w/ 3 boys that i go to school w/ were ping by and one yelled at me. i dont kno what he said. then other truck w/ like 6 boys (that go to my school) an one yelled at me again. i dont get it! what does that and all this mean?