Water landings mean you quite possibly won't remain upright.
Indeed - especially with fixed gear aircraft. I saw a C150 ditch many years ago and the aircraft nosed in as soon as the gear hit the water. Deceleration must have been brutal. When the spray cleared only the tail was above the surface and it was just over the vertical.
The sudden impact also shattered the windscreen so both occupants suffered immersion/thermal shock immediately after impact. The passenger (a pilot) said the disorientation resulting from being wet, cold and nose down seriously affected his ability to think and egress from the aircraft was far longer than he had thought it would be.
We operated from a coastal airfield and had discussed ditching many times. Nothing we had done (including wet dinghy drills) prepared them for the actual experience. Luckily both survived.