It's unexpected that you'll poop your pants as an adult.
Bob has had a bad stomach-ache all day at work, and is feeling an uncomfortable rumbling in his gut that's getting steadily worse.
Bob needs to figure out whether to run to the bathroom.
Bob makes a mad dash for the restroom, arriving just in time to relieve himself.
Bob decides to try and hold it until he finishes the task he's working on, but is unsuccessful and poops his pants as a result.
Bob's coworkers never really appreciate just how close they came to experiencing significant disgust, and continue working blissfully unaware.
Bob's coworkers are understandably revolted at what happened and make fun of him about it all the time from then on.