I'd say the customers most likely give reason for it. There are those terrible guys who get drunk and grab all girls their asses, often those men don't even have a shimei at the club though.
Then that type that you most likely mean, those who act really pathetic. For example a girl who's in a relationship outside of work, and her customer goes on and on about how he wants to get married to her. It does get on one's nerves i guess. Kyaba customers seem suprising enough more annoying than escort customers.
It used to be my dreamjob because of the beautiful dresses and hairsets, but now, after knowing better, it seems only a good job for me for girls who really want to avoid any sexual play with random guys. It does still pay double than a normal job, so why not, but for someone like me it feels like a waste of time!
Also with a lot of patience you can earn a lot from it, but at first, you get your hourly salary and most of what you see the guys around you spend goes to the club. Now i can justify taking a lot of money of a guy if its for me, but not if some club gets the biggest part of it. I'd only feel like eigyoing the guys because of the club's penalties.
As for hosts, yes, its getting lucky. If a girl enters a host club and falls in love with a boy and does as he wants, she definitely has more chance to lose all her money than to make a real boyfriend.