Have you ever been in a discussion with someone, where they're telling you how to do something and you feel like they're kind of talking to you like you're an idiot. So you draft a lengthy email with screenshots and descriptive text explaining to them that you've tried doing what they said, and as you can see in the screenshots it isn't working. You click Send and recline in your chair with a sense of smug satisfaction at your own vindication that you are not the idiot - they are.
And then... you happen to look at your sent mail and notice in the very screenshot you took that one thing you've been missing and which was there all along but you failed to notice. That one thing that solves your problem. And then the revelation pours over you like a bucket of ice water... you are an idiot. And you just made a complete ass of yourself.
Have you ever had that happen to you? I have. Just now.