The worst i had was a group of us went to remove a concrete block from a v gullied lane (which allegedly the farmer had pushed down the bank to block it). We parked at one end and walked up to look, noting that the 'farmer' had appeared in his truck and then drove away. By the time we had come up with our plan and walked back down loads of quad bikes and pick ups came up the lane with loads of farmer boys armed with shovels and bats. We were told to go or it would kick off!!!!! It was impossible to go because they were now blocking the road. If it wasn't for the fact that a couple of the guys had their young kids with them it would have turned nasty. Basically some other laners had been their that week and had been driving where they shouldn't have been seriously pi$$ing the guy off. to top it off a group of walkers came along and watched the whole thing, it was all quite bizarre and it did put me off laning for a little while.
Over the years i have encountered a lady who clamped her arms around a gate and refused to move, three times had farmers block the road to confront us and two years ago two of us had a couple of farmers chase us, overtook and then slammed their brakes on to stop us and wanted to know where we had been.
All of the above were resolved in the end, even ending up breaking into a friendly chat as we never doing anything wrong. EACH TIME the farmers etc were doing what they did due to other 4x4 drivers days or weeks before either driving where they shouldn't have been or causing damage to property, so to be honest i don't blame them for being annoyed. The problem is once some dick head annoys a farmer we all get tarred with the same brush.
It really is important to ensure you are on legal routes and to behave, people are watching and one idiot can create big problems for all of us nationally.
I have encountered other problems where either ramblers or locals are just being bloody minded and want the ROW to be kept for themselves but that is something we can't do much about.