I'll chime in.
When my previous wife and I moved into our then new townhouse, there was an odd sort of fellow in the one next door. Kinda quiet in a mildly sinister kinda way. You could just tell that this guy was troubled, but no more.
About a year goes by. We barely ever saw him that whole time. I got to be friends with the complex's upkeep staff. (Two guys. Great guys. Both hunters and general gun enthusiasts. Lotsa coffee and BS'ing took place.)
Anyway, once, the conversation came around to our next door neighbor. One of the staff guys said he'd recently had to go into the fella's place to fix a plumbing issue in his bathroom. (Bathroom is upstairs, right next to the master bedroom.) As he was leaving, the guy's bedroom door was open and my bud saw that the guy's bedroom walls were covered with newspaper. When asked what that was about, the guy's reply was, "So my neighbors can't see in."......ooooo...kayyyyy......
Well, like I said before, you could tell that he kinda had somebody else drivin' but seemingly harmless. Nevertheless, you factor in things like that in the course of any interaction with such a type. Well, whatever condition he had was gradually getting progressively worse.
At one point, he'd cruised past a couple of middle school-age girls walking home from the bus. He stopped his pickup and proceeded to graphically describe what "fun" things he wanted to do them. What he didn't know was that not only were those 2 girls cousins, but both of their dads were bikers.
And now they were riding around the complex with some of their buddies, all in search of our hero.
OOPS!
It's hard to tell what teed him off worse: How his life had suddenly gotten way more complicated or the fact that since these ol' boys were on the hunt, they asked everyone they saw if they'd seen him and let them know WHY they were looking for him. So as a result, everybody knew what he'd done and he knew it. Didn't see him for awhile after that.
Quick background. I've been a working drummer since 1978. The nut next door had seen me carrying drums in and out of my place a billion times. Once, he told me he'd fancied himself as quite a keyboard player. Well, ya just smile and nod, say "Awesome", and go about your business, right?
At about 2:00 AM that night, he decided to demonstrate his keyboard abilities by firing up his gear, setting the volume of his amplifier to "romulan stun", and puts it, speaker forward, against the wall that separated our bedroom from his. Rattling stuff on our dresser, the whole shootin' match. I told the ex, "He's a nut. It's one night. He'll pass out eventually." Turns he had lotsa stamina. Lasted about 4 hours.
Next morning, our neighbors on the OTHER side of him told me they'd reported him to the complex office. That night, he decided to do it again, only this time cranked up to Woodstock volume. More rattling, just absolutely outrageous. Much to the protest of my ex, I had an idea.
Ten minutes later, wacko boy was treated to 2 wide-open 26" bass drums up against our side of the wall, with me doing the closest imitation of the drummer in Slayer that I could muster. I heard crashing over there and stuff falling off his walls...no more Liberace jonesin' for his Thorazine.
I saw the other neighbors next morning and apologized and they said, "Hey, made him stop." Well, it also got him evicted. The noise along with being 3 months behind in his rent. He blamed me. Left a note on my front doorknob saying, "I won't forget." I informed the police, just in case something should happen.
8 months later, my son was born. Driving home from the hospital, my brakes went to the floor. Took the minivan to a mechanic who informed me that my brake lines had been cut. Coincidence? Who can tell?