There was a super insecure manager a bunch of years ago. I didn't report to him, but occasionally worked alongside him.

I had been working with one of our customers for a few weeks on a feature they had requested. It was something out-of-the-box, so understandably, if you didn't know the context, it would be rather confusing.

Manager is set to run a meeting with them, and asks for my help as the technical expert. No problem. We get into the meeting, and the customer asks some technical questions. Before I can get a word in edgewise, Manager proceeds to pull the most inane shit out of his ass for a good 10 minutes--clearly knowing nothing that's going on, but not letting that stop him. After the customer is sufficiently confused, and Manager is starting to look a little panicked, he finally turns to me.

I figure I'll try to save him some face, so I start my reply with, "I'm not entirely sure, but are you asking...", repeating their question back. The customer is clearly relieved that I know what they're asking, and I provide the answers. Crisis averted! The meeting ends and I head back to my desk feeling good.

Until Manager storms up to my desk and proceeds to scream at me, "IF YOU'RE NOT ABSOLUTELY SURE ABOUT SOMETHING, DON'T ANSWER! NONE OF THIS 'I'M NOT SURE' BULLSHIT! NEXT TIME THINK ABOUT WHAT THAT LOOKS LIKE FOR US!" and storms off. Nice projection, asshole.

I was new enough to not have the presence of mind to respond, so nothing came of it (though he was demoted not long after--possibly the shittiest manager I've ever known) so it all worked out in the end.