I've seen plenty of turbulance which has made people sick, and one very memorable flight in a CAL MD11. We hit some bad turbulence where my walkman ended up floating over 4-5" above my knee. Sort of interesting until it slammed into my knee. It was surreal, the overhead bins were moving front to back and the seats were moving left to right. After that experience I'm more paranoid of flying objects and hitting me than the wings snapping off and crashing into the ground.