Worse turbulence was probably during a skydive lift which caused the spotter (chap who lines up where we jump out of) to fall out of the plane (fortunately we were high enough).
In a commercial flight - the worse experience I have had (not that it scared or bothered me) but that caused me to wake up and not allow me to have a coffee, actually popped open some overhead luggage compartments - it didn't trigger the oxygen supply though as we only dropped a couple of hundred feet according to the captain (I asked him once we had landed).
It really isn't that scary, but for those who are nervous flyers, I can imagine it being hell on earth (or in the air) as for those people it is undoubtedly really disconcerting.
I'm a very passive flyer. I guess after spending 6-7 years of my life travelling weekly around the place you get used to it.
Unlike Will Gill who'd rather be lamped before getting on the plane