I see bad driving from loads of people on my 35 mile round trip to work and back, not just nit-picky stuff but fundamental mistakes that are just dangerous.
Not sure if it's an old/young/male/female thing (although there are statistics proving young males are more likely to crash in a big way) but one of the most dangerous traits I see is people turning right on a roundabout from the left hand lane when you can use both lanes to go straight across.
Obviously there are some roundabouts where this is permitted and there are signs to say use both lanes for right turns but otherwise you've got decent potential for a collision!
Then there's speed limits..... like others have said, some people seem to have no comprehension of what the NSL sign means or have a clue about lane discipline. The same people seem to have the attitude of "I'm doing the speed limit, I can be in the 'fast lane'" regardless of whether there are any cars in lane 1.
I know a lot of people are more conscious of fuel economy now and will stick to 50-60MPH to save fuel, that's fine on a single carriageway NSL road but if they're doing it on a dual carriageway/motor way they need lane 1 unless they're overtaking... simples.
While we're talking about saving fuel...... a guy I used to work with said his elderly mother drove EVERYWHERE at 56mph as she was told that was the most economical speed!!!
I got stuck behind a few Sunday drivers yesterday. Had to pick up an eBay purchase for a friend and whilst I was in no real hurry but it was around a 60min drive each way, I wanted to be there and back as quickly as I could whilst obviously being safe

So people who want to use the limits to their maximum to make good progress when it's safe to do so aren't just those who haven't left enough time and are late. Some of us have got better things to do than sit at 40-50mph on a road that we could safely do 70mph on. By making good progress where possible I saved myself about 20mins...... although I was greeted by my in-laws when I got home so perhaps I should have gone slower
