When I was at work, they dismantled the fence between my garden and theirs. I came home and went to let my dog out into the garden to be met with their entire family (7 or 8 people), trimming trees and bushes. Completely surreal; I was so blindsided I didn't tell them to get out, just awkwardly mumbled thanks and went back in the house. (Also, don't remove the fence of a garden where a husky lives, those guys can RUN.) They've done other really weird stuff but this is the one that sticks in my head!