all this suggests that a given performer is only playing to you (any individual). What about the people who didn't get to see the first performance. Is it perhaps too high an expectation to want a performer to play different sets each time they play. What about the songs that the people missed in the first performance. Why go to see the same artist more than once at any festival anyway? What do you expect? that they ask each member of an audience 'have you heard me sing/play this one yet' get real!!
chris