Yes if on the rare occaison I am just cruising along slowly I will leave a considerable gap in front of me, normally that of a bus/truck length so if anyone did one to weave in and out and progress on they can do so safely.
There is nothing more annoying then those who say all close up behind a truck or tractor on a country road and have no intention of passing, meaning I have to overtake 8-12 cars in a row to clear them all.
The other time I keep well over is for bikers, if I spot a biker I give them plenty of room to pass me safely. I think the drivers who purposely hover in the middle of the road are absolute idiots and if I was the biker they were doing that too on my way past I'd be putting my boot in the idiots door. Then there is those who don't use their mirrors, a mate of mine has now been knocked of her bike 3 times now, thankfully never seriously hurt but using mirrors would not hurt.
When I used to commute to Manchester from Stoke daily which involved country roads and dual carriage-ways it was amazing the amount of selfish idiots you'd come across, I guess I can be impatient but when coming off a roundabout why do so many insist on coming off in the fast lane when slow lane is empty and then proceed to sit their at 50mph? Maybe it was bad of me but if I was behind and after a short while they still had not moved I'd either undertake, flash my lights for them to move over or just drive on their bumper. I just get the feeling some people see a half decent car behind them and get some kind of pleasure at trying to hold them up.....
All it does is just make me more determined to get past, drive dangerously and take risk to get past the idiot. Or eventually they move over, you pass and they give you the headlights, which never goes down well with me, it normally ends in my slamming my brakes on in front of them, stupid I know, but its amazing how we all turn into barbariens once behind a wheel.