These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Fridge Brilliance: The full-auto pistol is noticeably weaker than even the Glock. This makes sense when you realise that this particular Glock is chambered in .40 S&W, while the full auto pistol is chambered in the smaller 9mm round
Genius Bonus: The Grenade Launcher introduced in this episode is modeled after the Heckler & Koch HK69. Could be a coincidence, but it's less likely than not, considering Rockstar's interest in the number 69.
Harsher in Hindsight: Billy Grey gets arrested by the police after a heroin deal gone wrong with the Triads. He blames Johnny for this, which ultimately leads him to go State's Evidence against the Lost and set up the final showdown. However, Ballad reveals that Billy actually meant for the setup to kill Johnny. Also, Billy's first action back from prison is to commit a murder on the doorstep of the Lost's clubhouse. You learn not two missions later that said murder causes the LCPD to keep an eye on said clubhouse.
Jerkass Woobie: The Lost themselves, or rather, what remains of them the end of the game can qualify. Sure, they're murderous, backstabbing criminals, but they didn't deserve many of the tragedies they suffered, because most of these were direct or indirect results of their involvement with the diamonds and heroin, which they just had the rotten luck of being roped into.
Moral Event Horizon: Take your pick from horrible actions in the game. Billy using the death of a friend to steal some heroin, bragging about banging Ashley, or betraying his so-called brothers for a reduced prison sentence all qualify. So does, potentially, Johnny kidnapping Nico's cousin Roman and threatening him repeatedly.
Most Annoying Sound: The pause music, which if you aren't paying attention (you have the game paused and your attention is elsewhere) just sounds like a car alarm going off in the distance.
Most Wonderful Sound: The triumphant guitar riff that plays during the autosave after completing most missions.
Paranoia Fuel: One of Stubbs' "Dirty Laundry" missions involves bugging Deputy Mayor Bryce Dawkins' Infernus to expose his secret homosexual affair with Bernie Crane. That same car is later given to Niko as a reward for helping Bernie. The fact that you're driving a car bugged by one of the other protagonists is paranoia fuel as is, but it gets worse. After the mission Stubbs gives Johnny a phone number that will let him listen to the bug. At first it's just Bernie singing along with the radio or thinking aloud about how Gay Tony's bodyguard is attractive, but eventually you'll start hearing the sound of a different Serbian guy running from the police. Yep, not only is it implied that Johnny could listen to Niko at any time without him knowing, it's actually possible in-game. Yet another reason to park that car somewhere safe and never drive it.
Player Punch: Interestingly, Player Punch scenes in GTA IV become missions here and vice versa. And Jim's death could qualify as one, considering how much time you spend with him during the game.
Stop Helping Me!: Did you know that you can call Terry and Clay for backup? Don't worry, because Jim will be sure to remind you at every opportunity. Terry and Clay themselves are plenty useful, though.
That One Level: "Buyer's Market", which comes close to The Computer Is a Cheating Bastard territory in terms of the amount of firepower Johnny has to overcome in order to survive. Made more vivid by the relatively easy "Blow Your Cover" level from GTA IV which is supposed to be the same mission but it's from a different perspective and in that one the player has backup. Fits the criteria for the trope as a number of players have complained about the level's difficulty on the boards (especially when compared to the GTA IV counterpart), while others have stated the mission isn't that difficult.
Uncanny Valley: Billy has an unusually wide mouth. It makes him look seriously off compared to the other characters.
Unintentionally Unsympathetic: It can be hard to feel too sorry for Johnny and Jim by the end of the game, as most of their misfortune was brought on by them stealing two million dollars from a mobster, half of which the main game shows he would've given them anyway. If they hadn't, Jim would still be alive, and his wife would still have a husband, his child a father. That Jim accepted the money at all only makes things worse, since he should've known perfectly well the dire straits his family would've been in if he died.