Why don't we seem to feel the time while doing something fun?

Question

And at work it just stands still..

Answer 1

cuz time flys when your having fun

Answer 2

There are different types of time, objective time (chronological time, time shown by the clock) and subjective time. What you are referring to is the subjective time.

Objective time is affected only at relativistic speeds (when we travel at speeds close to the velocity of light in vacuum).

Answer 3

Because time does not actually exist. It's a man-made perception. So when you are less aware of your own perception of time, it's speed can be altered.