We all enjoy people watching. Who, for instance, hasn't deliberately chosen the seat in the restaurant that offers them the best view of the other diners? Or even on a European jaunt, leisurely whiled away an hour at a town square café watching the locals go about their business? I didn't always observe runners any more than other people in the street. My interest in them was about equal to the man walking his dog. But ever since taking up running, I just can't help myself.
I am hugely drawn to them, making dozens of little observations about each and every one. "Funny running style"; "Nice shoes"; "Well-developed calves"; "Shades at night?!"; "Pretty speedy" and yes, I admit it "Nice bum".
There is no better time of the year than runner-watching as now. They are everywhere. I have no statistical evidence for this. I just know that when I am out and about and there is a runner in the vicinity, I notice them. I have been noticing them a lot recently.
There's little doubt it is to do with the time of year. The spring marathon season is fast looming. London, Brighton, Lochaber and Blackpool all host their marathons in April. Paris, Boston and Rotterdam are among the overseas events to tempt UK runners in the same month.
Factor in the scores of 10k and half marathon races taking place in the coming weeks - many of which are billed as marathon tune-up events - and you can see why the runners are out there. January is when runners launch their training, February is where people are really finding their stride.
My runner-watching is not just about pigeon-holing people; "He looks like a sub-3 guy", "He'll struggle to get round." It's also about learning something and taking a little inspiration. It even stirs emotions in me.
I may see a runner with a long stride. It makes me think about how I run, about my own technique. If I see someone with a snazzy luminous running top, it makes me think I want it too. But more than anything, if I see someone grinding their way up a steep hill, I take inspiration.
I know their pain, I know the suffering, but I also know the satisfaction too. Shouldn't I be doing that instead?