Fortunately not as serious as other comments. For context, I have autism, and I frequently stim by making random noises.

One day I was at a global online meeting with very important people. I thought I was muted, so I said “MEOW”.

Suddenly everybody goes quiet and somebody says “did anybody say ‘meow’?”

I quickly turned off my microphone, and fortunately nobody mentioned that again.

Not the worst, but the weirdest:

When I got my first credit card they told me that the very first transaction would be divided into 12 monthly payments, with no interest. So my first purchase was a new cellphone that I needed.

Later the same day I bought something for like a dollar, and just to be funny I paid it with the credit card.

Well, that $1 dollar purchase was also divided into 12 payments. Nothing bad happened because of that, but it just felt stupid.