I've noticed an interesting phenomena in my orchestra on the weekends when we play the same show on Saturday night and Sunday afternoon. Our Saturday night concerts are usually very exciting, but along with the drama comes an increased chance of technical sloppiness. Our Sunday afternoon concerts tend to be a little bit more subdued, but a lot tighter technically.
My theory is this: We get all jazzed up on Saturday night. There is usually a larger audience, and it's the first performance of music we have been working on all week long. Then we play the concert and afterwards we go out drinking. While drinking, we often discuss the concert we just played in great detail. (This need to rehash our musical experience is often very annoying to non-musicians, and I imagine it's a major downside to hanging out with orchestra members.) The next morning we wake up late because we were out the night before, we putter around the apartment, eat some food, look at the internet, and head off to the Sunday matinee. On Sunday, we are not exactly hung over, but we are kind of sleepy with that Sunday afternoon feeling. We play the Sunday concert with perhaps a little less zip, but with a lot more accuracy. We are getting the job done on Sunday.
Obviously, in an ideal world all of our concerts would have the emotional urgency of Saturday, with the technical focus of Sunday. Sadly, this is not an ideal world. Personally, I prefer the drama of Saturday night, but it never ceases to amaze me how a tricky passage that got the better of me on Saturday when I was all cued up, becomes a total breeze on Sunday when I am ho-humming my way through the concert.
This might be a little too revealing, as I believe our orchestra's official position is "we are full tilt all the time in an effort to bring you the most riveting concert EVER", but I think the truth is much more interesting.