Post something that one should never do, preferably because the outcome of such would be unpleasant at best.

Examples:

Never poke a sleeping bear with a loaded machine gun, especially if the bear is the one who is armed.

Never forget your mother and/or special someone on their birthday.

Never be found to answer the question after your lady friend asks, "does this make my butt look big."

Never go clothes shopping with your lady friend. If you don't know why, refer to the "never" just above.

Never post on GOG about how much you love Steam.

Never sleep in a nest of ticks overnight.

Never eat the yellow snow... Oh!, and definitely never eat the brown snow...

I mean there are so many things lol.
I would like to avoid impaling myself?
Or drinking a smoothie made of glass shards?

Never defecate in a toilet in a toilet store.
Never drink a can of beer in a church.
Never play hopscotch on crosswalk intersection.

Never say "religion is the opium of the people" while selling drugs during a service in church.

Never start tinkering by removing items from your motherboard unless you know what you are doing. Also, make sure you're grounded before you poke around.

Never hug a jellyfish.

Well, it ain't as bad as posting on Steam how much you love GOG. While the former might get downvotes, the latter would result in a ban for sure.

Chain is very probably a spam bot. Some of them copy previous post to make it look like legit posts. The spam links have been filtered out by the forum software for lack of rep.

Never pay upfront; always talk cash at the end of a(ny) transaction.

Never unveil your first and foremost priorities, true aims, real goals.

Never believe those who say they love, or are eager to aid (really dangerous, those friks).

Never stay in a rigged field/environment.

Never spend money on DRMed products; likewise, never support censor in both videogames and art, in general!

Never believe those who say they act, based on "your own good/wellfare".

Never fall for a volunteer's self-presented motives (always do bother to inspect behind the scenes).

Never let emotion get the better of you.

And the rest of the 57 "precepts of Bradley" (precepts of Zote).

Never noticed that before. I've become used to smarter spam bots that search for a game thread, then they search for a random reddit post that also mentions the game, and necro that thread with the reddit response. Of course, a random link is added to the response.

What you mention is an actual spam bot, whose only purpose is to flood the board needlessly.

Er...never eat Mentos and drink Cola? Fanta is okay, though.