Making mistakes while learning a language is obviously unavoidable, and the more willing you are to risk making mistakes the faster you’ll make progress. So it’s best to laugh about our mistakes and have fun with them.
So what’s the most embarrassing mistake you’ve ever made in a language you’re learning?
One time I was trying to say a full cup in Hebrew, and instead I said the equivalent of a full pussy.
My most embarrassing moment when was I was first living in Japan and riding the train. I tried to be polite by asking if I could sit in the open seat next to someone (“suwatte mo ii desu ka?”), but I actually said “sawatte mo ii desu ja?” which means “Can I touch you?” The woman looked rather confused and concerned until I pointed to the chair and she realized what I was trying to ask. 😆

Oh yes, I remember being very careful of how I pronounced COS.
It’s pretty easy to misread the word if no diacritics are written, especially if you’re not good enough at the language yet to know what the other word means.