This! I spent the first half of my career in QA. This second half in dev. Coming from QA I'm very meticulous about everything and yet as soon as it leaves my hands something comes up. This is why I'm a big proponent of QA. I had a chat with someone who was pretty much dismissing QA because they had the mindset of I'll just test it or my cofounder will help. It's terribly surprising what goes down outside the confines.

As a QA dev, myself, I run across this occasionally. For a recent bug, the dev couldn't reproduce it, yet I could consistently. The difference: the width the window we were using; he was using the default, I was not. Most of the bugs I run into are not config dependent, so it is always surprising when one is.