Parkinson's law

Where work expands to fill its allocated duration. This is the reason why we often see things like videogames being delayed, but rarely coming early. Related: Time pressure.

Reverse Parkinson's law

Sometimes when a low time limit is given, you actually feel more motivated to work faster. Though the problem is when you know it's artificial, you may not obey it... It depends on whether it's eustress or not. If it is, I'm happy with your productivity!