It felt like the back of a school bus going over a big bump in the road...
LOL...I know what that feels like
Anyway, I agree with heavymetal. Most of the people that are afraid of turbulence seem to be people who are afraid of flying, have never flown before, or don't fly that often. Many people feel that if they can't see or control the situation themselves, they start to feel threatened or worried about the outcome of the situation.
I don't mind turbulence, but I am also not a big fan of it. I believe that it was a Northwest Airlines plane (correct me if I'm wrong), that entered heavy turbulence, resulting in the death of a flight attendant and the many injurys of other passengers on the flight.
The heaviest turbulence that I have been in was on a BA flight (JFK - LHR). It was noticed ahead of time so the "fasten seat belt" sign was illuminated and everyone and everything was prepared for it. Some bags and other articles fell out of some overhead compartments when they opened up, but that was about it.