I'll play along, but most of these issues can be solved upfront if you communicate your expectations with your crew and educate them on your boat and the equipment. I kick them off pretty quick if they can't comply. Other issues can be solved with a bullhorn and/or a pellet gun...so I've been told.
Here's some items I thought of:
Lack of courtesey - pulling up right in front of your boat
Crappy water, crowded areas
More than 3-4 riders on a boat
Power turns-specifically sending rollers down the line
Hitting own rollers unnecessarily (turning for pickup)
Tubers / Jet Skiers- doing s turns in your line
Not paying attention
Not driving straight
Making an unpredictable turn
Taking in water over the front
Pouters "sniff, sniff, I had a bad run" sniff
The know it all (who doesn't)
The high-maintenance person ("I'm 2 hours late, come get me")-Sorry Charlie you have to wait long time.
The person that has to leave an hour after they show up.
People who have no clue: (Muddy shoes in boat, suntan OIL in boat, break your equipment (sorry, my bad), launching, docking)
Free loaders that don't get invited back and wonder why there is never room for them: No names, Chad, James, Sarah 2, Amanda, most of Christine's friends.
Any and all 5.0. Especially the CHP. All 5.0's suck bootie. (Only exception: the Sacramento SWAT TEAM are some really nice fellows - Ken, no offense.)
Rookies giving bad advice (or any for that matter)
But as much as this bothers me, I'll take a warm, smooth day of riding over work any day. And to repeat myself...."Most of these issues can be solved upfront if you communicate your expectations with your crew."