That's a tough one, but it's up to you to decide what kind of a man / human you will be in life. I think I understand that you don't feel like this guy is worthy of your attention or time so you want him to leave you alone. If that's what you're feeling, the thing to do is look in the mirror and ask yourself why you think the way you do? In every problem in life you want to solve, you have control over only one person; that guy you see in the mirror is the only one you control. Decide why you think what you do and why you feel it's a waste of time or degrading for you to give the guy the time of day. My guess is that you will realize you feel this way because you believe you're better than he is and he doesn't deserve your time and attention. If you feel this way, you better back up and readjust your attitude. Get to know the guy, find out about him and his life; why is he like he is; what are his life problems? Everyone has them and you would be well served to try and understand him and then do what you can to help. This exercise will transform you and change you and make you a better man. You don't have to be his best friend, just do what you can to help and you will be the one who benefits most.