My top ten ways to make your farrier happy (ier) are:
10. Present them with a clean and dry horse
9. Pay promptly on the day or as requested
8. Give them refreshments (tea, cake, biscuits etc)
7. Get the horses done regularly
6. Discipline the horses being worked on if needed – it’s not the farriers job
5. Don’t cancel appointments at the last minute
4. If there’s a problem, talk to the farrier first
3. Don’t ask the farrier if he can do a barefoot trim like you’ve just read about on the internet!
2. Turn up on time for the appointment
1. Be appreciative – saying thanks is free
Farrier Blog 
Yep number 10. It never ceases to amaze me how many times in winter you pull up only to find some idiot smiling at you and saying (wail hosing the horse) just getting the mud off for you. so now you have wet legs, wet feet, wet muddy slippery ground, steam and thats not counting the minus 3 deg early morning start.