An eight year friendship (back then, that was half of my life) ended exactly like that. Towards the end of secondary school he just completely blocked me out. Then I mentioned it to another friend (who I have known for that time and longer now, we'll call him friend B) if he's noticed that friend A is being odd, and he said "What do you mean, he's always a dick". That's when I though back and realised that, yes, in fact he is an enormous penis. So I shrugged and went on with it.
Edit: What I can say with certainty, however, is that friend B won't do that for a couple of reasons.
1) He is more mature (as am I)
2) I can't remember a single time in 5 years where we had an issue between us. He used be get upset at me a lot at really minor jokes, but I always apologised, then one day his skin basically quadrupled in thickness and I don't think either of us has offended or hurt each other since (not that he ever found the ability to upset me). Physical hurt is all too common, however, usually one of us smacking the other for doing something idiotic.
3) We also never have arguments that last for more than a minute or two. Partially because we never talk or argue about anything "real" or that matters, but partly because a good few seconds shouting and swearing at each other does wonders, and it never feels too serious.
Another thing that happens is that we never stop insulting one another, and I know that this is a common thing, but you know you have a good friend when you greet each other with "Oi! ****!".
I would recommend these as advice, but frankly, they will do far more harm than good if you aren't quite as close as you thought, or if the other person takes offence at things such as these, also, seeing as though I have one friend, I cannot claim to be in any position to offer social or friendship advice.
