I've been chasing a bug in one of my computer programs for almost a week, now. It was driving me nuts! Complicated math formula, depends on lots of messy real-world phenomena. I was positive I was calculating it correctly, but it kept producing an obviously wrong result.
Stared at it until stupified. No joy.
I finally decided to ask some smart people for help. To avoid wasting their time, I wrote up as simple and clear an example as I could.
I instantly saw my error.
Life lesson in there.