This topic, again? Oh Escapist, you should know better than this.
Here's the thing. The reason why I think that this topic rouses such strong responses is that people are just terrified that they might have inadvertently been some girl's "Nice Guy", or indeed some guy's "Stone Cold Heartless *****". But this isn't exactly a dilemma that can only be solved through the application of quantum mathematics, fuck-in-hell, you don't even need a working knowledge of algebra.
If someone else treats their doormat with more common decency and respect than they do you, you are not their fucking friend. If you allow yourself to be treated like an absolute doormat, and prostrate yourself before them without a shred of dignity or self-respect, you are not their fucking friend either. Friendships work off mutual respect. The overwhelming majority of time that you spend together with your friends should involve sharing experiences that you both have an equal interest in pursuing for their own sake.
Sycophants and those who enjoy their attentions, whether they're ignorant or aware of the role they play in their twisted relationship are incapable of an honest friendship. In these circumstances a friendship cannot be betrayed, because in truth it never existed in the first place.