I'm thinking of giving up on a close friend.
Did you friend ever do anything to you to deserve being given up on?
They are self-centered, have always been late, don't trust me.
You are really disappointed in your friend, which is clear to me. Be there for them anyways, one day you can prove your friendship was worthwhile to them. Giving up makes you seem like you are too lazy to try which that means you were probably the reason why they don't believe in you.
I thought she was the only one that would be able to understand me, o well.
Come on, don't give up that easily. Quitting like that is not being there for them.