A lot of good responses on here. Some that haven't possibly been mentioned:
On profiles:
* chav\text speak "C me 2day 4 fun"
* heavily airbrushed pictures or outdated ones
* pics were the stomach is covered, something to hide?
* Shit tatts airbrushed out
* 10 commandments, negative bullshit, blatantly biting the hand that feeds
* long meandering essays stating the obvious
In the flesh (things I've experienced)
* Big pants - just because the woman is a "BBW" doesn't mean she has to wear Mrs. Brown's bloomers, a pair of french knicks please.
* Little or no effort made - wet hair, chipped nails, wearing a tracksuit, crusty feet etc.
* fake moans and the obligatory "oh baby"
* Constant talk about their kids or hubbies - I appreciate they may love them, but talking about them is boring to listen to and ruins the facade. It's also quite offensive on your paid time.
* Shit music\commercial radio\ any music full stop.
* an alarm set early\constant clockwatching.
* Being wanked off constantly\blatant ploys to make me cum quicker etc.
* 10 commandments.
* Added "extras" not mentioned.
* Turning her head away when going in for the "smooch" - what is this a fucking Ritzy nightclub or paid sex?
* texting constantly or answering phone calls - a big no-no.
* wild goose chase directions
* "have you got my money?" as soon as the door opens.
Stuff mentioned on other threads, but not experienced by me
* Used condoms drying out on a washing line
* Crusty bath towels
* A wet shower that a previous punter wanked in.
* Passing punters on the stairs
* The escort farting, pussy farts I can deal with, not the other end.
* The escort burping.
* The escort taking a shit during the meeting.
* period stained sheets - nothing to do with Victorian textiles
* spunk stained sheets, even worse if it's her son's Man U ones.
* "Babbies asleep in next room"
I could go on. More turns me off than turns me on. Maybe I see it too pessimistically.