Some people were waste products or a-holes, but can change. One guy I thought was a waste product got a PhD in Sociology. Don't let what the person was bother you , You may have been one yourself, but the other people may have gone through more changes tha you. If the person is still an a-hole, just say hi and move on to others.There are plenty of people to talk to. Besides, you may never see them again or see them in maybe 10, 20,or more years,