Not a lot unfortunately. A new neighbour recently moved in to the house (and garden) that runs along my back fence. The previous owners planted all sorts of climbing plants (hydrangea, pyracantha, ivy, rambling rose, jasmine, etc), all down their side of the fence, which came over the top and came over into my garden, which I didn't mind because I just incorporated it into my garden. It also provided some screening / privacy between each of us. Unfortunately, they moved out and new lady moved in and she has completely decimated EVERYTHING in her garden including removing all the climbing plants on the fence so all I have now is a complete blank fence. To add insult to injury, when she removed the plants, she chopped the climbers off at the top of the fence so everything that was growing on my side just fell I to a heap on my side of the fence and squashed all my plants growing there. She didn't come around to ask if she could take it away and just left it to me to clear up. Took two weekends to clear it and take it to green recycling in my car (my petrol). Somebody said I should have thrown in back over but I'm not one for conflict and as a new neighbour I wanted to give her the benefit of the doubt she would evenaturally pop around and apologise. She never did.
I spotted her the other weekend taking pruning shears to another neighbours ivy climbing over the other neighbours garage, with the only offence seemingly that because the garage runs along her garden she thinks she has a right to chop the ivy back.