In the 80's, when synths kicked in and killed the music business for acoustic instrumentalists, we used to toss this one around:
Q. What's the definition of an "optimist?"
A. A trombonist with a beeper.
This era was very hot for wedding bands. Here in New York, the agencies that booked "pick-up" bands (throw- togethers that actually sounded very good sometimes) they could never find enough "leaders" for these bands. Often, the band leader would be some obnoxious, arrogant dude with extremely limited vocal ability but an appropriately large set of cojones to handle all the corny MC work and, perhaps, yell his way through the wedding couple's first dance. One of the most popular jokes to emerge from this era was:
Q. What's the difference between a wedding band and a bull?
A. A bull has the horns up front and the a-hole in the back.