How dare you park in an unassigned spot that I might use at some point
I live on a street with free unassigned parking. There is a row of units next to me, which has a driveway and a parking garage for each unit. Most of the rest of us park on the street. But an older couple in one of the units is absolutely obsessed with reserving the spot outside their place. They never seem to actually leave their home, they just seem to always be watching that parking space. They'll peek out of their door and make disapproving noises, or they will come out and ask you to leave because it needs to be left for them. It is absolutely not, in any way, legally their parking space. And they do have their own garage.
Today, it was the only free space, so I parked there. The lady emerged and said I needed to leave because she had a 'truck delivery at some time today'. I replied (politely) that unfortunately it's not an assigned space and there's nowhere else to park. She said 'just be kind', which hit a nerve because I reckon I am quite a kind person. But then she called me a 'bloody bitch' and a 'shithead'.