What to do when you've fluffed it...
a) Rescue the situation the best way that you can and apologise to the pony; they know what's in your soul.
b) Examine the cause, your ego, your skills, your mindset and where you went wrong; check your heart is still in the right place.
c) Vow to learn from it - something always happens before what happens, happens; make sure you can spot that next time and do something different.
d) Actually learn from it!
e) Remember all the good things you have done. Remember you didn't do it on purpose, that you are always trying your best with the best that you know and that you have a right to make decisions and sometimes they will go wrong.
f) Move on.
Things that are useful to have: An 'all stop' system where ANY member of the team can say 'all stop' if they feel that something may be too great a risk. Always build in a margin of error - remember the horse's adrenalin is like a balloon and you are not the only one putting air in. Dynamic risk assessment all of the time - this doesn't mean you never take risk, just that you are always calmly conscious of it.
