Timely thread and lots of great responses. I totally get it, friendships and my friends are extremely important to me. I've often stated that it's the only area of my life where I've ever felt like a complete success...I have great friends. Some I don't see very often because of either geographical or lifestyle differences but I know who I consider a friend.
That said, I have personally failed at friendship before and also jettisoned several former friends for various reasons. In recent years, I've let go of a few...one last summer in Minneapolis that was a bummer but I don't regret it. He is someone whose entire family was very close to ours at one time, (parents were friends and neighbors but that entire generation is gone), he and I were close but he has extreme health issues that I have spent a lot of time helping him with, (always willingly). I feel bad for him but the problem is that his issues have made him so unhappy and mean that he takes it out on people around him, including me. He used to be a happy guy and now he's just simmering most of the time...he blew up at me over some minor thing last summer and I walked away knowing that I'm done talking to him. I still care about the guy but need to take care of myself as well. I've cut loose a couple of other people for variations on the same theme though not necessarily physical health issues caused it...sometimes it's mental health. I can only be around well balanced people at this point in life or I'll catch what they've got.
The so-called friend in the OP was never a real friend. The definition of a friend is someone who cares about your well being, period. Not someone who never annoys you or pisses you off or bores you...real friends will do all of those things if you spend enough time with them. I've always been a big believer that you accept people for who they are, warts and all, or cut them loose. That neighbor sounds like he doesn't care about you at all, he just needed someone to hang out with at the time. I know that it's painful but it's not a reflection on you...it's a reflection on him. Some people just aren't very deep.