Don't try to be a smart-aleck lazybones.
If the coffee pot only gives you half a cup and you have to make a new pot...
...don't get all "clever" and lazy and stick the half-filled mug under the drip spout.
(Especially when your coworker advises you that this is a Bad Idea.)
Because the black coffee is dripping out of a stealth-ninja coffee maker in "silent attack" mode.
It is dripping dark liquid into your shadowed, dark mug.
And you have no depth perception anyway and can't tell how full the mug is.
However, when the coffee starts running over the top of the mug, you will know that it is full.
And now you have a big mess to clean up.
And you realize that it would have been faster to simply wait until the pot brewed.