When I lived with my mother, we had parking spaces at the rear, that never used to be allocated, until one annoying neighbour, ****ed off that she couldn't get the space she wanted all the time complained and demanded that we be allocated parking spaces.
So once the management company sent us a letter, I asked for the space that she wanted - being that it was probably closest to my house, I thought I stood a pretty good chance of getting it, and sure enough, I did!
After this, she would continue to park in what was now my space, if she didn't her numerous visitors that she'd have daily would!
I just use to park close enough to hold a coin between the bumpers, so they'd have to come and knock on my door and apologise to get their car out.
On a completely different occasion, a friend had someone park in front of his garage, with his car stuck inside, and unable to open the door - he called me and another friend up, and we rock bumped the car out in to the middle of the road and simply left it there - thirty minutes later the police were there, five minutes after that they had located the registered owner - I'd have loved to have heard that conversation!