An intercity bus at a Bulgarian bus station gets filled with passengers. At some point, the bus sets off, and starts accelerating.
However, the passengers see that a man is desperately running behind the bus and trying to catch up. Thinking he is a passenger who is late they start laughing and shouting at him,
"Dude, don't run so fast! We're gonna pee our pants laughing over here!"
The man managed to reply to them, gasping for breath,
"And now you will sh*t your pants! I am the driver!..."