That's the word I was searching for. It is a word from a German review describing Cecilia Bartoli in Giulio Cesare in Zürich. It is very nice indeed to watch someone who really enjoys their work. In Germany acting isn't considered work, though. Spielfreude is literally translated "play joy." I'm looking forward to seeing the opera. Of course, I must also put up with the three countertenors. I'll let you know how it goes.