why care for someone who doesn't give a crap about you

I had a friend who was pretty good friends with me for over 8 years. We hung out and and had a lot of good memories. Well, they were good to me at least. After a while i realized that he was never really there for me. A lot of my old friends and even new friends told me that i shouldn't trust him. Being the nice person that I am, I disregarded everyone and their warning. I gave him the benefit of the doubt to only have him screw me over multiple times in the few years. I just care because we were good friends, but now that I've seen the true colors, I couldn't give a crap about him. So never should you EVERRR care for someone who doesn't give a crap about you. It'll only hurt you at the end.