DH got pulled over once for driving "suspiciously slow". He thought the policeman was joking. The truth was he was driving a beat up old Kingswood that had a dodgy speedo so he just drove carefully.

I stick to the speed limit. I find it astounding that I'm always tailgated in the 60 zones (and under) yet when it moves up to 80+, I lose the tailgater. Drives me mad. It's slower for a reason. But I also get frustrated sitting behind people who are driving 20kms+ under the speed limit - especially in an open road where there is room to the side to pull over and allow the traffic behind them to pass.