So, you need the loo.
You get to the communal work toilet and are about to adopt the position when: BAMMMMM!
There they are. Someone else's dirty deposit tracks, looking right back at ya.
a) Not give a shit. And still have one before leaving.
b) Have a slight sense of shame on their behalf but just leave them be.
c) Feel the need to clean them off begrudgingly in case you leave the cubicle and find a fellow member of staff staring you in the face, and forevermore thinking you to be the guilty trailblazer?