I wouldn't mind so much if Justin Wateridge was some gritty, super-fit Para. Or an Olympic oarsman.
But he's a 43-year-old travel agent from the Cotswolds and just happens to be a man with more than his fair share of resolve.
I found myself alongside Justin at around the halfway mark in this year's Virgin London Marathon and I'm sorry to say that after a couple of hours of running in close proximity, I'd had enough of him.
Justin was wearing a 6ft 8ins rhino costume weighing 25lbs and was obviously attracting almost fanatical support from the crowd.
I struggled along in my lightweight Guide Dogs running vest to a deafening chorus of "Rhino, Rhino" and "Come on the Rhino." It got pretty irritating.
At around mile 23, when I was oblivious to almost everything except the discomfort in my hips, the rhino chanting subsided. I'd clearly left it behind.
But guess what? When I checked the finishing times the morning after, there was my desperate 5.16.30, leaving me in 27,048th place, seventeen minutes slower than Justin Wateridge, aka The Rhino. That's it. Enough.
The truth is, I've never really enjoyed the marathon. This was my sixth in seven years and it had become an increasingly painful obsession. The past winter has not been a good one for ploughing along the Thames path into an icy wind. It's not as if I was improving. I ran my best time in 2007 and have been progressively slower since. Hours and hours of effort to be beaten by a bloke dressed up as a rhinoceros.
So thanks for the memories, London Marathon, for all the brilliant volunteers who make this such a memorable occasion. Thank you to Guide Dogs for letting me join their team, and to all the people who have sponsored me. I've decided to stick to half marathons in future. And a healthy diet of rhino steak.