I was on a LAX-DEN flight, prior to takeoff, captain announced that first half of the flight will be bumpy and second half of the flight will be even more bumpy and preparation for landing will start 40min before landing. FA said they might not be able to provide full service during the flight.

After takeoff, there were barely any bumps all flight. Luckily FA did their regular drink service for the entire cabin.

And when we landed, the lady next to me said "That was the smoothest bumpy ride I've ever taken."