In a recent discussion, a professional retriever trainer was telling his tale of the ecstasy he'd experienced waking at 3 AM to get to the airport by 6 AM, to get his pup on the 7:20 flight - already booked. It turned out that since he'd done it last, cargo pushed their open hours back significantly... Bottom line - flight missed.
We then talked about some other issues that put some kinks in the day and made the actual act of getting out there and training some dogs seem like the easiest part of the job.
He quoted one of his fellow dog pros:
"Dog training is the easiest part of dog training!"
I'll leave it to you guys to name the pro quoted. I bet he's said it more than once.