Not really the worst, but my hot take of something I don't like: puzzles rather than problems. By that I mean puzzles have one correct solution and everything else is wrong and doesn't work, while with a problem you're given some tools and an obstacle and just let loose. It's so much more satisfying to find your own solution that it is to reach the end and realize you were being sneakily handheld through it to make sure you found the only possible way through. I've done a few good problems where I reach the end, then immediately reload the save from before and try some different routes just to see if it works.

Puzzles do have their place though, especially in tutorials.

Holding a button to do anything/everything. I can see the logic of where it may be useful, but it doesn't need to be used for everything. So damn annoying.

*Oh, and similarly, forcing excessive submenus to do basic things, like continue a save from the main menu. That should be one, maybe two button presses, not 4+ along with a confirmation. I'll never understand games with stuff like that.

Escort missions

Stealth challenges on games that don't have stealth as a regular mechanic

Anything that makes you follow an npc that doesn't match speed with the fucking player

2 sets of teeth, the first only lasting 1/9 of your life and the second being 8/9. 2/9, 7/9 would be much better or just 2/9, 4/9, 6/9.

Oh, hair falling out and all your joints hurting for 5/9 of your life kinda blows as well.

QTE

Weapon durability

Ante, Magic the Gathering

Lootboxes

No natural health/mana regeneration. I hate games where you need potions to survive or are limited in your spell usage just because you do not enough mana which was finished earlier.

Unskippable cutscenes. Escort quests where I have to walk slowly.

Pay to win.

Limited inventory space in an otherwise unrealistic RPG.

You're telling me I can carry six two-handed weapons and 500lbs of gold, but seven is just too much?! Fuck you and the horse you rode in on.

Specifically, this especially sucks when the inventory is a grid, like in the Diablo series, or Grim Dawn, or WoW, FFXIV or... many other MMOs.

especially when you can spend real money to alleviate the artificial limitation they fucking designed in to the game.

It's so unnecessary and these days absolutely makes me instantly not care to continue playing. FUCK artificial limitations that don't have clear, valid reasons.

I'm here to play a game, not Inventory Management Simulator 33.45

Button-mashing events. (The Rapid-fire kind)

Relationship mechanics. If I give someone a pumpkin twice a week, they’re just going to be confused and pissed.

Something that hasn't been mentioned: difficulty variations that only change stat penalty. These get really annoying for people who enjoy challenging gameplay...

Case in point, unmodded Skyrim's legendary difficulty where the only difference is that you do 0.25x damage and take 300% damage. Instead of providing challenging gameplay that forces you to use gaming skills or think, it just makes the game more annoying to play & limits player build options (stealth is mandatory as any other playstyle deals no damage and results in you getting kill-animation'd...)

The skulls in MGSV.

"Let's put almost unkillable, magic zombies that chase you into this stealth game. Also, make them unavoidable"

Timer that can be skipped with paid currency.

Underwater swimming on a game that wasn't built around it. Every single time it's a frustrating battle with poor camera angles and imprecise controls.

Oh I'm above the thing I need to collect but slightly out of grabbing range, all I need to do is go straight down... And now I'm 20ft away.

Anything that is 100% chance and just wasting time, with no meaningful way for the player to influence the odds. For example, how fishing is implemented in some MMOs like ESO: you can eat a buff food and use the correct bait for the water, but beyond that you're just waiting in agony until the random timer dings. Then you do that 12 times before moving to the next hole, etc. "Waiting" isn't an enjoyable mechanic.

Anything pay to play ruins it for me.

Not the worst, but I'm annoyed by invisible walls. Just give me a reason why I can't be there.

Games that have long scripted sections you can't skip and sometimes even save. Next level, you'll have to move around and answer questions so can't even go take a shit.

Witcher 3 and Cyberpunk both had sections like that. Loved the games, hated that bullshit.

Poorly done procedural generation where it's a waste of time to explore. The first Remnant was pretty bad about this, with small setpieces scattered throughout the levels that looked interesting but usually only contained basic enemies and one or two empty pots. Filling out the map was a chore that was almost never worth the effort - almost never because sometimes there was a unique drop hidden in a level just to screw over anyone who got sick of fighting through hundreds of empty buildings and decided to stick to the main path.

"Here's a rare weapon dropped by this boss! But wait, you need to be at least level 30 to use it, and you're still on level 2."

I went out of my way to repeatedly grind and kill this late game boss during early game, just give me my reward for not following the stupid linear progression

How about the release broken game then finish the game way after release… if you’re lucky mechanic?

Exponentially growing requirements that out pace rewards. I don't want to spend 10 hours grinding just to level up.