Getting trapped in the corner til your buddies finish.

If you are first to choose and you choose one of the corner urinals, then as soon as you start everyone's big gulp is causing them to storm in. Since your choice of urinal is indented a bit closer to the wall. The people that would choose the direct center and outer urinals would have their shoulder and body behind yours, causing you to wait for a path to open up.

It's a public urination phobia nightmare to some people.