Please report dangerous drivers to the police - Roadsafe. Report to plod, not just whinge here.

I once did that very British polite thing with a driver who was making a right turn into a car park while I was going straight. I was slowing down anyway for something up ahead so gave him the "after you" nod to which he replied with a "no, not at all, after you" nod, then I did another "no, certainly not, wouldn't dream of it, after you" nod and then at some point we both did the "oh alright so kind of you, thank you so much" movement forward at the same time right towards each other. I can't remember how we both managed to escape in the end but I seem to remember the dance being a long and protracted one.

Anyway, the moral of the story is that eye contact and body language are definitely only part of the story and you need to make decisive and obvious actions in traffic so as not to leave as little to interpretation as possible. Goes back to what wvm says about firmly establishing right of way - if you're hesitant then people tend to interpret it as a deliberate pause to let them proceed, especially if you're making eye contact with them at the same time. In the main I don't make eye contact with drivers unless I'm actively negotiating with them, and if I've got priority that only really happens when I'm giving way as a courtesy. I still watch their cars (especially the wheels) to make sure I know if they're going to pull into me, though.