Why poke an argument with a spear when a trident will give you more points?
Many would be the motivations for developing levels of performance in music... and certainly working for the purely aesthetic goals is most honorable.
However, I do suspect that there is a great deal of competition--and all of competition's dark brothers and sisters jealousy, pride, shame, fear, and anger--among artists when they are both preparing to perform and actually perform.
There is the performer who insists on having private rehearsals with the musicians before rehearsing with the larger group out of fear that her rehearsals are not to be heard before she has reached an excellent performance level. In other words, she keeps the larger group from moving forward together because she has an inflated sense of how wonderful she needs to sound before she is publically heard, even if only in performance rehearsals. Her personal mythmaking about self she continually manipulates. Pain in the butt to work with because this kind of perfectionism wishes to make one who is not godlike appear to be more godlike. And it causes the musicians to carve out (just for her) still more rehearsal time in an already crowded schedule. Some people are more equal than others.
