Fun scale:
Type I fun: Fun while it's happening, fun in retrospect
Type II fun: Heinous while it's happening, fun only in retrospect
Type III "fun": Not fun at all, not even in retrospect

Cycling for me is majority Type I fun, and as such, is easily understood.

Sometimes, a ride can turn into Type II fun, and while such rides could plausibly dissuade me from ever cycling again, they usually make for excellent stories.

If cycling were unrelenting Type III "fun," I probably wouldn't do it.

But fun is, of course, subjective...