Each day many people from all over the world come and visit me, however they usually only stay for a few minutes. I am considered by many to be very dirty yet few people would want to live without me. And, whenever people come see me, they reveal to me a part of themselves that they rarely show to others. What am I?

Emily was gossiping with her friends and told them that she was sure Josh was a drunk because she always saw his car parked in front of the bar. Josh overheard this and decided he was going to use his car to get back at her by making everyone think she was easy. How did he do this?