When Getting Lonely

It's good to deal with people how you like people to deal with you and this is my way in life, but some times you saw people who don't deserve to talk with them " Like one guy I know he is really have nothing to live I wish if I can kill him cause even I always talk to him and ask him if he want any thing or need any thing, more over when I saw him angry I ask him if I can help him and why you are angry.
At the end of all what I did to him I discover that I shouldn't do any thing good to him even saying " Hello ", today I saw him and I want to see if he is going to say hello, but like always HE NEVER CARE ABOUT OTHER just like himself, while I'm talking to a friend he said " hello " to my friend and didn't care about who is talking to him so I said " there is some one else standing here , he look back at me and said so what I don't care and many thing else . Here I wish to kill that guy and really make me angry.
I didn't reply cause if I will reply I will make some thing very big and might kill him :p
Should I do some thing else and go and talk to him face to face or just ignore him ?