Of course, the test difficulty depends on what you're doing, and on how you're doing it. I'm constantly asking "How much would I have to screw this up to write an incorrect function that passes these simple tests?" Occasionally the answer is "Not much," so I'll throw the code away and start over. It was probably perfect code, but that's not good enough.

Daniel J. Bernstein
Another Quote

You Can't Manage Stress Unless You Do These Three Things