Without more specific details to give you advice in this particular case, I’ll give you some of my own approach to when behavior of other people bothers me. First, in this case, since it’s not clear, the first thing I always try to do is what I like to call the generousity interpretation. For example, say someone says something that’s offensive and it makes me angry (unlikely, but let’s just run with it). Rather than reacting as if that person either intentionally said it to hurt me, what other motivation could that person have had in saying it? Maybe they just aren’t aware that whatever they said is offensive or is a sensitive topic for me. Maybe that person even said it and felt ashamed enough about it that their response is to just sort of pretend it didn’t happen and kind of forget about it. Maybe that person said something that I took as an offense but they really even meant it as a compliment and I just took it out of context. That motivation may or may not be correct, but I have found that far more often than not, people don’t intend to be jerks, it’s just a misunderstanding or someone having a bad day or a simple mistake, and then it escalates to the point that hostility eventually does enter into it. Someone cuts me off in traffic, maybe I was in their blind spot, and it’s not like they can just turn around and apologize. Just hope it’s that, and let it go.
Now, maybe there just isn’t any reasonable interpretation that doesn’t make that person not a jerk. Maybe you’ve been very patient and asked nicely and he’s just like “go fuck yourself, I hate you and I’m going to make your life a living hell” or something. You still have to ask yourself what that person’s motivation is, and you can realize that a person can only get to you if you have that same sort of issue. As a bit of a weak, but obvious example, it’s like if you are a reasonably intelligent person, no one has ever doubted that, least of all you, and someone just keeps telling you that you’re stupid. If you are confident in your intelligence, it has no effect, but if you are lacking that confidence, it will quickly get under your skin. This applies is more esoteric ways as well. Maybe in this case, you one time parked to close to his car, he way over reacted and started parking next to your car for revenge. You have to ask yourself WHY that particular behavior would spawn that reaction in him, and why that reaction in him is making it so difficult for you to let it go. Maybe it’s respect? He feels like you disrespected him, so he’s disrespecting you and that’s why it’s getting under your skin. Well, why should someone who is going to deliberately be disrespectful, which inherently makes him not a respectful person, who misinterprets a minor mistakes a grave form of disrespect, make you feel disrespected? If you can get that confidence in the idea that the respect or disrespect that type person is irrelevant to your own self-respect, then you’ve rendered that behavior powerless, and it’s easy to let go.
Basically, the idea is that pretty much anything that another person can do that doesn’t actually blantantly cross the rights/legal line, is something that you can render powerless by reflecting on yourself rather than just seeing it as being that person. And, of course, if they do cross that line, where he’s damaging your property, then you need to get the authorities involved. Short of that, it’s really just a matter of understanding exactly why it bothers you as much as it does, and once you do, it’s a lot easier to just let slide.
And beyond that, until you can get to a point like that, find a good way of letting it out without involving that person. Any time you react to him, it reinforces his desire to do it. If you’ve accepted that asking nicely won’t change it, then any other way you need to let it out, make sure he has no idea. Maybe tell a friend, or listen to music, or exercise or meditate. Don’t complain to neighbors or post it on facebook or whatever. Eventually it just won’t be worth the effort anymore and it’ll probably at least get less severe, and it’ll make it that much easier to just let it slide.