I'd like to see a reply that focuses on "arbitrary" instead of "irrational" (from the phrase, "Attraction, humor, joy and love are very often irrational and arbitrary"), or maybe there is a better word still, considering the standup example.

Comedy seems like a fruitful domain to explore this frame, since there is no apparent criteria to optimize for that isn't "arbitrary" fundamentally: jokes age poorly, and don't translate to other cultures or contexts well. They rely on surprise to be funny, but also predictability to be legible as jokes. Jokes both are constrained by and escape their formal properties, necessarily.

"I bet we can do better" can't be the domain of optimization alone, it has to come equally through indifference/the arbitrary; it's a dialectic.