There's nothing like going to an office bathroom and seeing that all the stalls are full, or just slightly better that they are all full except for one that just seconds before has become vacant.
And the colleague that just came out of it looks at you with a big grin saying "Good luck!" (true story.. x_x)
And I shower during work hours.
An afternoon "shake the after-lunch drowsies" shower is truly a glorious thing.
That, and also workout during compilation. Which does also seem good for concentration, so win-win?