What's the worst thing a neigbour has ever done to you?
I'll go first: he tried to block the sale of my home at the last minute. We were 50% freeholders, with him owning the other 50% (technically our homes were masisonettes but I always referred to it as our "house"). He didn't like the person we were selling the house to (based off a brief description) so attempted to block the sale and said that he was "sorry and good luck when you put your house back on the market". Our lawyer wrote him a letter to remind him that although he was 50% freeholder, he was not entitled to say who we sold our 50% share to based on personal preference (you can't hold auditions for neighbours!). He was shocked that we got lawyers involved (it's almost as if he didn't realise buying a house is actually quite a serious legal commitment!). Very nearly lost us our sale and caused us a LOT of stress. But all worked out in the end when our lawyer threatened to pursue a breach of contract on his part when he refused to sign some paper work over a personal preference on who would be buying the property. Then had the audacity to say we were ruining his life - you chose to buy a 50% freehold, mate, no-one forced you!
But I got my (very petty) revenge: Just before we moved out, he put up CCTV on his property looking into our (private!!!) garden and on to OUR drive - presumably, so he could keep an eye on the new neighbour once they moved in. It was one of those ones that activates and sends an alert to your phone if it detects movement. I am an early morning outdoor exerciser so would make sure to do all of my starjumps and lunges on MY drive at 6.30am right in front of the camera and was always very amused to see the little "activated" ring light up, followed by the lights coming on as he clearly checked for an intruder - I hope you enjoyed the 6.30am wake up alarm a few times a week, Mr!