As a long-distance trail runner, I’m no stranger to poo. I’ve lurked behind bushes in the dead of night hoping that no-one notices me and I’ve face-planted in finest Lake District goo which I tell myself is pure, unadulterated mud despite the laughing sheeps. I make a mental decision to leave a certain amount of prissyness on the shoe rack every time I put on my trail shoes, and devour any articles I find which assure me that immune systems, like muscles, benefit from regular workouts.
But when I run under an unremarkable tree on a pavement in deepest suburbia and emerge with a handful of guano my squeamishness knows no bounds and I want nothing more than to chop off my own arm and dive into a bathtub of Dettol. I didn’t, obviously. I wiped my hand on the nearest bush, made a mental note to wipe my forehead with my other mitt and finished my run as planned.
And then I came home and chopped off my own arm.
abradypus 
On the one hand, this could be described as brilliant…. But on the other, it’s a bit of crap.
I’m still recovering (both from the poo and the crap joke)
I am going to choose to believe that statement refers to you recovering from extended periods of laughter in response to a description of the subject matter of the joke as opposed to its quality.