Let me share the moment in my life when I felt the most stupid. An inconsequential situation, thank God, but it scarred me mentally.

We had a lunch with a very important business parter of my boss, an investor. When he says:
"- I collect tomato."

And I replied, most brilliantly:
"Oh! But for how long can one keep a tomato until it rottens?"
(As I said it, I sensed that something is very wrong, and that it is probably me)

This investor guy put down his utensils on the plate and looked my in the eyes for a few seconds before answering:
"- It is of course tomato PLANTS I collect!"

He must've thought that I'm an idiot who thought that he is an idiot. And my boss sitting next to him wondered with his face what is wrong with Tsunamibomb today.

A couple of lessons learned from this mental scar:

First, if someone makes a seemingly outragous claim, like collecting tomatoes, do not automatically assume that he is a madman (although that is a real possibility). At least consider having misinterpreted something you know nothing about.

Secondly, only ask a question when you expect a certain answer, one of a few alternatives. Asking a question is to require that a decision be made. If you do not know something, then do not ask about it. That's why one should never answer a question literally (professionally, in private life one is allowed to be stupid).

What did I expect him to answer? Picking up a tomato out of his pocket:
"- This one I've had for five weeks. It's getting a bit saggy and stinks, but it's still in my collection."

I did get the conversation going somehow anyway, and he talked about his sophisticated botanic culinary hobby. Tomatoes are apparantly closely related to potatoes, who would've guessed. But my boss retained his impression that bringing me along to important meetings is crazy risky. "I collect tomato." Yeezys H Christ.