The worst turbulence I have ever experienced was some years ago on a flight from New Orleans to Cincinnati. It started not long after take-off and continued unabated for most of the flight. Everyone was required to remain seated with seat-belts buckled for the entire duration of the turbulence, which ended really only about five minutes before landing, when we were well down in altitude. No food or drink service, since all the cabin crew were seated. No visits to the lavatories, and in truth one would almost certainly have fallen over on the way there and, had one eventually got there, hit one's head on the ceiling in the lavatory.
At first I was terrified, but then I recall thinking, quite suddenly: "what's the point?" and just settling down (as well as possible) and making the most of it (if that makes sense).
My other main memories of the flight are of the man sitting across the aisle from me, who periodically took large gulps out of a bottle of Scotch whisky that he had with him (this was before any restrictions on liquids on planes), and of a number of passengers using their vomit bags – it must be unusual in these days of jet travel for adults to be plane-sick, especially in large numbers.
All most unpleasant. Delta gave everyone food and drink vouchers for use on arrival at Cincinnati and also for use on a subsequent Delta flight.
I did notice that lots of the passengers repaired to the first bar they passed in the terminal after leaving the plane.