Challenge? Playing at hardship, making hard work of it, damn difficult but bloody ludicrous …
My only challenge is to finish the day happy and contented, having thoroughly enjoyed myself.
Absolutely this.
I can see the legitimacy of abitrary challenges for the advancement of fitness / charitable benfit of others, however I find life challenging enough without adding additional, entirely-constructed hurdles.
As such I find much greater reward in challenges that yield more immediately tangible, real-world benefits such as the classics "return from the commute having avoided the bloody, firey death of yourself or others" or "recover the weekly shopping without wantonly sh*tting into the open mouth of the planet to appease your own lazyness and consumptive social conditioning".
That said I did have a favourite hill I'd smash it up in an effort to beat my own PB / induce a fatal heart attack; either of which would have been a welcome outcome.
HTH