Until San Andreas, in GTA world 'wet' always meant 'dead'. This wasn't necessarily a huge problem with GTA III, since you probably deserved a drowning if you managed to dunk your vehicle in the nearby sea. Though that's not to say it wasn't terribly annoying when it happened.
But you were never more than five seconds away from a humiliating drowning on the streets of Vice City's Miami-esque island cities, resulting in an endless number of infuriating deaths. How on Earth did we not get more angry about this oversight?