This is true but I'd say the biggest issue is people having no patience. Not everyone is a road warrior, ultimate driver who can do no wrong. Dorris taking an extra 5 seconds to merge because she last joined a motorway in 1970 shouldn't be a trigger.
People have no patience for anyone else on the road and assume everyone is of the same experience level/can make no mistakes.
I admit that I'm an impatient driver, but I get what you're saying. It's easier to bear if you can put it down to inexperience or nervousness.
But there are times when it's seemingly purely down to selfishness, laziness and/or entitlement, and it's that which I find the most infuriating - when you know another driver has not put in the merest bit of effort which could help others. Not indicating for example - literally all you have to do is extend your little finger and nudge a stalk, and the chap waiting on you at the mini roundabout then has a bit more of a clue as to your intention, which might help him move off a bit quicker. Same for lane hogging and discipline - I guess sometimes it's inexperience, but more it seems more often to be pure laziness, as far as I can tell. It's easier to cruise in the middle lane, so people do so, ignoring the fact that it means more legwork for everyone else to manoeuvre around you. But hey, as long as you're alright, Jack.
That's the sort of "poor driving" I think we suffer with most in the UK - a lack of consideration for others around you, and putting in a bit of effort, even though it might not be technically or legally required, to make everyone's journey a bit easier.