From USA Today:
Difficult neighbors can get under your skin. “Choose your battles wisely,” says F. Richard Blue, a psychologist with a private practice in Atlanta. “Your ultimate goal is to solve the problem rather than get angry.” Try these solutions.
Borrowing. It’s one thing to ask for a cup of sugar; it’s another to borrow a drill indefinitely. “Try . . . saying something like, ‘I know you forgot, but I really need my drill back,’ ” says Susan Newman, psychchologist and author of The Book of No. If she’s a habitual non-returner, the next time tell her you’re not comfortable lending that item.
Messy yard. You landscape your lawn while your neighbor’s looks like a jungle. Try something like, “I’m having guests over this weekend and wondered if you could mow your grass.” “Your neighbor will get the message,” says Newman. “However, if your neighbor is simply lazy, understand that you can’t change people.”
Noisy neighbors. Whether it’s a barking dog or a blasting stereo, it’s within your rights to ask them to keep it down. Ask for what you want changed, such as, “It would be great if you could turn down the music after 9 p.m.” If the noise continues, try sending them a note stating you’ll be forced to file a complaint if the noise doesn’t stop. Your last resort is to call the authorities.