I have one...
I live on a large lake, but the cove I live in is narrow and shallow (in the winter, when the Army Corps of Engineers (ACE) lets out ~10 feet of water). Our dock has a longish fixed pier onto which the floating dock is attached. Fixed piers are not normally allowed by ACE, but ours had been exempted by the original owners because the dock would be unusable otherwise (the water closer to shore is just too shallow). By regulation, docks must be >50 feet from each other and ours is 40 feet, but again it was allowed by the regulating authority (ACE). The 40 foot spacing does not impede anyone's progress; there are no docks after the one that is 40 foot catty-corner to ours.
One year we had the fixed pier repaired as it had been damaged in a storm. About two years after that, a ranger from the ACE came by while my wife and I were at work. My neighbor spoke to the ranger, who explained that the owner of the catty-cornered dock had called to complain about how close our dock was. "We usually prefer that neighbors work these things out themselves, but he has called us every single week for two years to complain about it." She took some measurements, left, and we never heard from them again.
I went to speak to the guy. I knocked on the door and when he answered, stuck out my hand to shake his and introduced myself. He said, "I know who you are" and refused to shake hands. I was very calm and cordial in asking what the issue was and how it could be resolved, but he started cussing about how close our dock was and he was going to have it completely removed and our dock permit revoked. Keep in mind that I had spoken to him several times over the years when we were both at our docks, and while we had never formally introduced ourselves the conversations were always pleasant and cordial.
I talked to my other neighbor (the one who had spoken to the ranger), who is a 70+ year old lady and is the salt of the earth. She said she had a run-in with the guy a few years before that. While in her yard, she thought she heard someone screaming from the lake area. She thought it might be a cat wailing or something, it was indistinct and her hearing is poor, but she went down and said, "hello? hello? hello?" several times from our dock before going back home. Later that day, the guy bangs on her door and barges into her house, red-faced and screaming at her. "You fucking wise and beautiful woman! My wife fell and broke her hip and you left her abandoned in the driveway when she called for help!" He then left, but she's convinced that he would have hit her if she hadn't been holding my infant son at the time.
Thank God that guy moved at the end of the summer.