It is definitely fun to do what your friend did, Rapaire. I even had the opportunity to do it--I had bought 20 Dutch Apple yogurts at the Super Giant (of course this is in the US). I love it--with cinnamon in the recipe. A little German girl behind me in line said to her mother (as I can recall) "Du, Mami, er hat 20 davon! (Mommy, he has 20 of those!)   So I turned to her and said "Stimmt". (That's right). She turned beet red.

There are lots of good reasons to speak more than one language--that's really a very minor reason--but fun.