The Urinal Effect is based upon an individual's inability to properly maintain control of their stream at a urinal. The Effect compounds upon itself as proceeding individuals are forced further away from the urinal as the lake of urine continues to grow beneath their feet. The theoretical size of the resulting lake is infinite, until properly sanitized by a janitor.
"Dude, there was a horrible Urinal Effect in the Cici's bathroom. I had to stand 5 feet back."