It seems to me that there is a fine line between innocent jokes and full-blown juvenile behaviour. The amount of effort you would need to invest into sustaining such a place is not worth it, best to just not allow it at all. There are plenty of places where you can get your dose of jokes and fun. One thing that keeps immature and rude people away is precisely the "dullness" that the post above speaks of. People get tired and move on, leaving the place clean and tidy for others to use.
HN has problems of course; downvote bullying is one of them. I'm not saying HN is perfect, but I'd rather not turn it into Reddit or Youtube. So I don't know where this leaves HN between the "pub" and "commercial street".
I come here because it is one of the very few places where you can have interesting discussions and read interesting comments from people with a similar intent and interest.
The café was the first pub-like place where people did mostly not drink alcohol. Reportedly, it was an inportant place for the enlightenment period of history. Let's not oversell HN here, though...
Some years ago, a friend introduced me to caffè corretto - espresso with grappa. Pretty good stuff, too.
Some of the most brilliant people in history also had an often juvenile sense of humor. Hacker culture was born out of puns and memes and Discordianism and Monty Python references.
But we don't do that here. We're serious people having serious discussions on serious topics. Look at how serious we are. Like that monocle guy meme, except replace the glass of wine with a can of Gamersupps mixed with adderall.
Well if you are looking for memes and catposts, yeah, the S/N ratio here is quite low.
Honestly I think of those things as noise, so I see S/N of HN as much higher. I can always go elsewhere for the vibes.