There comes a point in many games of 1KBWC where an overabundance of cards becomes problematic.
Think the opposite of the Thermonuclear Card Winter. This is hideously annoying. Everyone may have 30+ cards in front of them.
At some point, the increasing point values that come with an increasing card count turn 1KBWC into a exercise in maths. If it goes on long enough, score values fly into the hundreds of millions. Cue the inevitable Rezero.
Probably the most annoying variant is when the majority of cards are cards you really don't want to play. This can be a result of low standards for cards to be kept in the deck causing deck sizes to explode over 400.
Blank Hand Clutter
This variation is when all your cards are blank, so you need to create a lengthy delay in gameplay.