Goes both ways, ladies:
Not refunding money or adjusting next month's bill when you've clearly been overpaid for the month (as you insist on being paid in advance, it makes it hard to adjust easily when there have been sudden changes to the schedule)
Further to above, being the first to complain about not being paid on time (read your contract, I ticked "in arrears", not in advance. How was I to know that you expected to be paid before you had done any work? Unfortunately, I don't get that luxury!)
Expecting a present for doing what is essentially YOUR JOB (I don't gripe when my boss doesn't pass me a little something something at Christmas) - if you're not happy with a biting toddler, then say something, rather than expecting a bribe
Sending a message to a parent saying, "Oh, my DC has been struck down by a D&V bug but you're more than welcome to send your DC in if you'd like"; basically saying I'm "available for work" (when you clearly aren't) so expecting to be paid regardless
Sending a message to a parent saying, "Oh, my DC last puked yesterday morning, so it's ok to send your DC in if you'd like" for exactly the same reasons as above
Further to above, when I send my DC in 24 hours after they have last vomited (after most likely contracting said bug from CM's child), complaining that they ought to be kept off for at least 48 hours after as you "have to protect other charges", totally ignoring or not getting the irony of your statement
Feeding young toddler charges without bibs which have been sent in by parent, thereby ensuring that DC get more food than is necessary caked and dried all over their clothes (of course I love doing extreme laundry just so you can do without bothering to use a bib)
Claiming that my DC's poo is "not normal" - it is not my fault that you have never taken care of an exclusively BF baby before
My DC doing a poo just before I come to pick them up and you handing them over in their dirty nappy without even asking whether I would be happy with you changing them first
Dressing DC warmly when leaving my house and explicitly saying to you that they need to have a layer removed when indoors in your house; yet, DC return to me at the end of the day with heat rash from wearing their jumper indoors unnecessarily
Handing my DC over to me saying they've had a bit of a poo explosion but may have some left on them after you cleaning them, so I should probably give them a bath. That's what I always want to hear - you implying that you may not have cleaned my DC adequately 
I could go on, but I'll stop now.