Got stopped by a very nasty copper for speeding a few years ago and whilst he said everything he could to wind me up he did ask a valid question that had a point.
He asked how long i had had a licence, i answered at the time about 25 years.
And he simply said, 25 years and you cant tell your driving over the limit.
The reason i say he had a point is because if you drive along without looking at the speedo and try and get the speed of the car right in a 30 you will find that nine times out of ten when you look at the speedo your almost bang on if not a tadge under.
Next time your out there give it a go, its surprising how all those years do give you a memory for how the speed should feel.
I should point out that his reason for saying this was because my defense was that the speedo was in kmh and not mph and i though i was about right.
A lame excuse and he proved his point.
On the plus side
He gave me an NIP and put the wrong date on it and i got away with it. It was the turning point for me though and i decided to try and enjoy my riding/driving and not just the speed.
I too am now capable of having a que of cars behind me in a 30mph. Always makes me smile.