I don't do raves - so I can't compare...
But ... always the worst gigs are the 7 to 12 piece Funk-Corporate-Greatest Hits band.
Always, always..
Demanding on patience - as in "the band" - and everyone around them are clueless, burned-out wannabees.
Always an argument between the band about monitors.. "I can hear his monitor, can you give me more me?" - and then the next one chimes in, "he's too loud, can you give me more me? - and so on.
Guitar player (always a semi-burned out, never-could-get-a-tour ex-hippy) wastes precious sound check time working on his "magic tone," and "has" to have it (the tone) fully reproduced in his monitor, even though the amp is 3 feet from his head. Always too loud.
The horn section can never agree on anything, and each usually has a "special" mic that they've brought. I've had some whack jobs bring precious vintage figure 8 condensers that they "always use in the studio."
Keyboard player has an old POS, with bad connectors and schitzo patches. Bad cords.
Rhythm section is easy:
Drummers are just hearing impaired (that's an easy one.)
Bass players are just cool.
Always a random "percussion player"
Band says "Kick is too loud," drummer says "more kick."
Band says "guitar is too loud," guitar player turns up.
Half the band does not want to hear anyone else - even though they are standing 3 feet from someone who wants "everything."
Everyone in the band is a soundman, and everyone has a different opinion. All opinions are given at once.
And then the band-leader and the cute/young lead singer deign to arrive - and the whole process starts over again...
Please don't get me started on corporate event planners.....
And please, please don't get me started on the "eclectic mix of styles."
(oddly - straight R&R "classic" cover bands are usually pretty easy)