The things I hate in video games.
Bad Glitches:
There are two types of glitches, good glitches and bad glitches. A good glitch is a glitch you have to look for, something like super jumps in Halo 2 or breaking through an invisible wall in a game after hours of work. A good exploit to a game is an exploit that takes actual skill to use. A bad glitch is a glitch that you don't have to look for, a glitch that isn't fun or an exploit that's super easy. Some bad glitches can completely ruin the gaming experience, like a game crashing or freezing, it can be very frustrating.
Lack of Checkpoints:
A game that has fewer checkpoints is harder and more frustrating. Some of the most annoying things is going through a difficult 30 minute section of the game for the 100th time, it no longer becomes fun and becomes a serious drag, not even the sense of accomplishment you get from finishing that is enough to excuse the sheer annoyance of these super far checkpoints.
Restricted Freedom
That part of the game where you're running through a house and everything is exploding, you feel like you having real fun, until you realize you can't move left, right or back, in fact, if you let go of the mouse you'll notice you'll still be running through the house. A game like that, cutscenes made not to look like cutscenes, tick me off quite a bit. Certain games that have committed these horrible crimes include societies favourite Call of Duty and Battlefield games.
Bad Lag:
Like the glitches, there is good lag and bad lag. Believe it or not, good lag is a lot of lag, so much lag that the game becomes unplayable, you realize the game is unplayable and you go to a different server, or maybe you stay and watch all the random people teleport and game-breaking things happen like mounted guns slipping off their vehicles and random bodies flying all over the place. Bad lag, is just a little bit of lag, that little bit that means the game looks playable, but it's lying. You will be running around a corner and see an enemy, you shoot him and take him down, expecting him to go down, but OH NO there was a 0.1 second delay in your shot, so he survives, shoots you just fine, then calls you a noob. Lag is a gamers biggest troll.
Overpowered Items:
Oh, OP weapons are very nice at first. You will pick up this weapon or vehicle and think, man I can kill anyone with this! THIS IS AMAZING! Oh, how wrong you are, because it may be so fun to be on the winning side, it is never as much fun when you're on the other side of that muzzle. When someone else has an OP weapon, you will know the true pain and anger for the weapon, you may decide to boycott the weapon, OH but that will fail you because now everyone else still has the weapon and you're at a disadvantage, this mainly became a problem with helicopters in GTAIV.
Hackers:
One of the largest pet peeves of mine is a standard modder/hacker. Someone who copies a script someone else created in order to give them an artificial advantage over the game. Some hackers can be fun at first, they may have a pink gun and be in a banana suit and it's all fun and games, then they might start killing you so you try to kill them back, only to realize they're invincible, then when you try to kick them, your game crashes. Oh hackers, why do you have to exist? I don't understand what is fun about a game with no challenge. Single Player mods can be fun though.
The Community:
My last pet peeve with games is the community, not all of it obviously but there are a few aspects of the community I like. With the aforementioned hackers, the very stupid trolls, the extremely naive and annoying squeakers and of course the MLG "professionals". All of them I try not to associate with, most of them for obvious reasons, the only one not obvious is the MLG professionals. They usually have such a smug and outlandish attitude about them that it boils me up to see them tell me what gun has the greatest bullet per second spread and how I'm a noob because I didn't go the most efficient route. At the end of the day games are meant to enjoy, if winning is the only thing about the game you enjoy then fine for you, but to some of us the experience of the actual game itself is fun as well.