what things that can cause to end up a friendship.

I agree with you. A few of my friends have lied to me before, but nothing MAJORLY important, so i don't hold it against them, because in the long run, i know they're not a nasty person inside etc. But betrayal, such as a friend doing something behind my back with my partner, or stealing, i don't think i'd be-able to forgive them so easily, i'd want to know there excuse, but in the end it would probably be our friendship over.

Well sometimes what happens is that a friend leaves you behind because he or she found someone else whom he or she likes better..sometimes some friends gets tired of spending time with the same people so they tend to find someone else who is newer and more fun to be an accompany.. Sometimes LOVE gets in the way too..when a friend gets too serious about the relationship,the friendship sometimes gets left behind and sometimes even forgotten.. There are alot more simple reasons why friendships are breaking apart..maybe their world isn't just the same for the friendship to last..