I dunno man, my old neighbors have forced me to do shit like that.
At my parent's house right now there are 3 junked cars parked on the line just to piss them off. They have sued me 7 times because I "Own too many cars". They call the police on me when I work on them (They won a court case saying that I could only work on my cars if I put up a tarp to cover it) and they walk their dog to my driveway for it to piss on my tires.
They also won the ability to come to my driveway, and note my plate numbers down. They do that occasionally to piss me off. Sometimes they leave notes on my car (I FREAKED when I found a note taped to my steering wheel, because I didn't lock my doors) (The note said "Do not drive you car up this part of the road after 9:30 at night or we will call the police. Park at the end of the road")
A little background on my grandfather. He was a self made real estate mogul that grew up in a suburb of New York City and then moved out to the rural area of New Jersey. Had 5 kids, lived in a nice quiet, respected neighborhood.
Fast forward to when he's 65. White trash neighbor moves into a smaller house on the main road on the side of my grandparents' place. He brings all his crap cars that sit on his yard and are beaten up with him. He's outside at 2a.m.-4a.m. grinding away and hammering on these piece of trash cars, he doesn't have a garage to work in. The cars start becoming lawn ornaments along with stuff like jetskis and mowers. He turns his house into basically a used car lot and starts buying and selling cars like crazy. My grandfather asks him to stop and then he starts getting pissy saying he could do whatever he wants even though 1) he's breaking noise violation laws at late hours, 2) using residential land as business land, 3) he's been in and out of jail all this time and the cops are looking for him and 4) my grandfather catches him shooting a pellet/BB gun at the garage door of his house.
Long story short, the guy was a scumbag and after my grandparents had lived in the same house for about 40 years, he finally chased them out of their house. The neighborhood has deterriated since then and now I haven't seen my grandparents in 3 years after they moved out to Montana. Basically, I hold the guy personally responsible for my grandparents leaving New Jersey because he was the straw that broke the camel's back. He wasn't the only reason why they left and he didn't physically make them leave but he made their quality of life become poor. Rather than being the nice old man my grandfather was he started become bitter and resentful because of trailer trash people like this guy.
To have a neighbor complain about you can be irritating but if you're breaking the law and doing things that you certainly shouldn't be thats irritating them, they have every right to complain. If you're not doing anything thats harming them, depreciating the value of their home, or depreciating the quality of their life then yes you should keep your mouth shut.
With that said, I don't think I could bring myself to do anything like this idiot did, especially not to an old woman.