I was always pleased when I learned that an ensemble in which I played was going to play a piece I'd already played with another orchestra. The best example of this was Franz Schubert's eighth symphony, "Unfinished." During one rehearsal, I was playing it with fierce confidence, going to town as if I'd played it several hundred times by memory. When the conductor stopped the orchestra to go over a particular passage, he looked over at me and said, "Very good!" The seriousness with which I replied, "Thank you," elicited a few giggles from the first violinists.
It didn't bug me at the time, but later, I thought, "I wonder if I was approaching a 'Be Not Afraid' level, instrumentally."