I'm not bothered by learner drivers. After all, everyone has to learn at some stage and most of the ones I see are capable of doing the speed limit. I find it's only really noticeable when they attempt slow speed moves (pulling away etc) and I can wait an extra 2 mins.
Sadly, I've got no time for HGVs playing "who can complete the world's longest overtake?" because they pull out at 0.00001mph quicker than the guy they've been following for 14 miles. On a 3 lane motorway it's mildly annoying but on a 2 lane stretch where you get stuck behind them for 20 mins whilst they jostle for position... die.
Even worse than that is to see them ever so slowly creep past the truck they are overtaking until they get to a hill and the overtaking truck cant keep up his speed and you seem him slowly drifting backwards to once again start pulling forwards again when they get to the flat/downhill again.
Grinds my gears!
Especially on the A66 when the overtaking truck will take the entire section dual carriageway to complete this maneuver (or fail and drop back behind the truck again) and then everybody is stuck again for another 5 miles on the single carriageway until we get to another dual carriageway bit and the truck driver attempts the overtake again!