One reason why some conductors appear disgruntled: Not unlike the manager of a sports team, the conductor is expected to elicit sound musical performances from an orchestra.
When this doesn't happen to the extent it should, concertgoers may react the way my mother did in the '80s. It was the orchestra's first concert under a new conductor. He'd spent the first three weeks rehearsing only the first movement of Dvorak's eighth symphony. Then, he repeated this process with the fourth movement of that symphony, leaving insufficient time to rehearse the second and third movements of that symphony, Haydn's 88th symphony, and a Mahler piece.
Mom's verdict: "I think they had better results under the previous director."
She wasn't wrong. Pacing rehearsal time properly is critical for a conductor, especially a new conductor.
