Everyone's got their own pet peeves with respect to the D&D rules. Some people will find that theirs have been addressed in the 2024 revision, others will find that theirs have not. Looking through the various reviews, I came across two that still kinda irk me.
1) First Aid: I know we're playing a game, and that if they made it harder to do non-magical first aid, no one would bother with it; however, the idea that you can stop someone from dying (regardless of whether they got stabbed, slashed, burned, acidified, etc) in less than 6 seconds simply by expending a "use" of a healer's kit is, frankly, miraculous! Imagine if modern battlefield medics could save their comrades lives that quickly and easily! (Think of the scene from Saving Private Ryan where the medic gets hit and his squad mates fumble about trying to save his life.)
This issue doesn't bother me as much in a sci-fi game, where you can explain it away with a quick "stimpack" injection or the like. But it does bother me in a pseudo-medieval fantasy game, where nonmagical healing techniques ought to be slow and somewhat awkward.
2) Knocking Someone Out: Again, I know we're playing a game, and this rule seems to be based on movie logic rather than reality; however, the idea that creatures remain unconscious for an hour or more* is a bit ludicrous. In reality, if someone is unconscious for more than a few seconds, they're essentially in a coma and are likely to suffer brain damage and may not ever wake up. I had been toying with the idea of changing the 2014 rule to 1d4 rounds rather than hours, and I may still do that, as I'm not sure I like the auto-short rest rule.
*In the 2014 rules, it was 1d4 hours; in the 2024 rules, it's 1 hour (because short rest).
What rules annoy you (either mechanically or conceptually)? What, if anything, do you like to do about them