EMSOAB: Terry Pratchett Has Ridden Hunt Hirelings...

and certainly staff horses.   Adapted from "Moving Pictures":

"Victor was introduced to the horse. It blinked its long eyelashes at him and appeared to chew soap. It looked like a horse that had had a long morning and wasn't about to take any shit from anyone. So far it had kicked three people.

‘What's it called?' he said cautiously.

‘We call it Evil-Minded Son of a Bitch,' said the groom.

‘That doesn't sound like a name.'

‘ ‘S a good name for this horse,' said the handler fervently.

Victor leaned close to the horse and whispered, ‘Look, I'm a friend, OK?'

Evil-Minded Son of a Bitch flicked a carpet-thick ear.

‘How do you ride it?' he asked the groom.

‘When you want to go forward you swear at it and hit it with a stick, and when you want to stop you swear at it and really hit it with a stick.'

‘What happens if you want it to turn?'

‘Ah, well, you're on to the Advanced Manual there."

EMSOAB should be on LOTS of stall nameplates.