Imagine stepping out of a metro as a stranger in a hectic, crowded station. Now you want to reach Neumarkt, a rather central place in Cologne.
Look for 5 seconds at that sign. Which way would go?

If you’d walk right, be comforted. You’d be not the only one fooled by that idiotic sign.

What can we learn for software from that?
To a developer, it’s clear how her software works and how it needs to be used. So we rely heavily on testing by and input from others.
Use bug reports as an important source of feedback!