No i wouldn't drive up someone's arse anyway. Certainly not an oldie. It's intimidating.
But that is why they cause accidents, it's the frustration of being stuck behind 'Noddy'
I have used my horn, usually if someone in front doesn't move when the lights change.
I always slow right down for people on horseback (a lot of country lanes round here and often get the odd horse) Also some of the lanes do not have any pavement for pedestrians so if i see someone walking i would ease off the gas a little.
I have stopped to help lone female drivers, or women with kids, if they have broken down. Done that once and she used my phone and i stayed with her till the AA arrived because she was really nervous about being there as it was late. Sorry guys, but a bloke got in my car at the traffic lights once and i am wary about men.
I also have stopped traffic to let women with pushchairs cross the road, and old people. I am a courteous driver but i do get vexed when i am stuck behind a noddy.