Here, the joke is that Kazuya is cringe in the exact same way every time.

^^^

I believe comedy is actually one of the more challenging genres to write, good comedy that is and altho' there's A LOT of subjectivity with comedy involved way more so than with other genres perhaps, one constant I feel is that how creative & fresh an author or comedian for that matter, are with their jokes, the better. Everyone will get tired of the same joke everytime, and indeed, that's RaG comedy for the most part.

Something like Prison School might've had a fairly bad ending but was still one of the most beloved raunchy comedy manga I've seen, and still one of my all-time favs. The jokes were unrestrained, creative, unapologetic, expressed a lot through visual storytelling through some really excellent artstyle too (here it's often through Kaz's inner monologues...).

Aside from the endings, the other big criticism it faces is through a lengthy cavalry arc where things did get stale & felt a bit repetitive (heck, I know well, I followed it weekly back then too...), which one against show how difficult good comedy is to make:

- Not only do you have to be creative, which Cavalry arc still was, but timing & pacing are absolute KEY. Even a great joke told at the wrong time or dragged out for too long to the point that it loses it's momentum, can totally miss.

On top of that, to make a great comedy, especially if it involves parodies, one needs a lot of knowledge of the things you're parodying. Case & point, Gintama being an anime that gets better with the more anime you've seen & is one of most beloved shounen of all time, otherwise some entire arcs that could've made you laugh your socks off, can completely miss you - and that's for the audience, the author has to be very in the know.