Okay, we've had the thread where we have commented on things the Swiss get wrong in English. But it's only fair that we parade our own mistakes as well. But only if you want to....

Mine was confusing auf and mit during a set of private lessons. I said "Ich tanze auf meine Frau". After my german teacher stopped laughing and managed to regain some sort of composure, he said: "Yes, I suppose there are situations where you could dance ON your wife".

Now, three years later, I can see the humor in this mistake....