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.
Alternative Character Interpretation: The first game suggests that the Dude is truly being targeted by the townsfolk of Paradise, however, the presence of a moving truck outside your house in the first level has led some to conclude that he's gone insane because he was foreclosed upon.
Cult Classic: Mainly Postal 2 as it is the most well developed compared to the first and especially the third game.
Dude, Not Funny!: The rather blatant violence against certain groups (animals, random civilians, police/servicemen) smacks a little too hard if brought into the light of reality.
The game's initial start-up screen is the developers blatantly stating that this type of violence should stay in the game and not be played out for real.
"Funny Aneurysm" Moment: In Postal 2, you have the option to kill Gary Coleman (canonically, he dies whether or not you kill him), which, if you killed him, has the Postal Dude ask his wife how much an autographed book can sell for. Remember this game did star Gary himself, and was made before his death...
Game Breaker: The likely reason that the Apocalypse Weekend expansion does not have a multiplayer component is that the new melee weapons are so much more effective than, well, every other weapon in the game.
The 2013/2014 patches have gone some way to avoid this - whereas in earlier versions of A Week in Paradise you could get the machete five seconds into the game, now it takes significant effort to find anything of comparable power before the halfway point. And then Enhanced Mode goes straight towards this trope, with higher-powered weapons being much more plentiful, and new bonuses such as no upper limit on any ammo type.
Good Bad Bugs: There are several - lighting yourself on fire makes the instant-death fire harmless, dogs can float up ladders to get to you and propel you skyhigh, and one well-aimed rocket lets you skip the "Confess your sins" and "Uncle Dave's birthday" chores.
You can prevent the Parents for Decency from storming the RWS HQ after you collect your paycheck just by dropping a grenade in the path of the one guy who rallies them all up to go forth and kill you and the RWS guys. When the in-game cutscene plays, he sets it off and dies, and the rest just stay there. It won't prevent some scripted protesters from showing up to attack if you try to exit out the front door, but it does mean you won't get shot in the face the instant you regain control of yourself and have much fewer people to fight off.
And you can trade him a signed Gary Coleman book for a Krotchy doll to skip the entire sequence. Or just buy it off of him (any amount of cash seems to do, but he'll take all the money you're carrying).
Meat World, specifically the final stretch where you have to fight your way back out of the building that is now swarming with cops and SWAT. After you've likely used up all the health items in the area and the SWAT are much tougher and better equipped than the butchers you just fought.
The Military Base to the end of the game are a long string of these in Apocalypse Weekend. Starting at the Military Base, like the Brewery, all of your items are stripped upon starting the level. Unlike the Brewery, however, upon finishing any of the level, none of your previous items are returned. Made worse by the fact that some of the items you were using don't appear in the base at all, meaning that they are officially Lost Forever. Plus, the Military Base is LONG, clocking in at four parts altogether. Adding on to that, the entire level is absolutely swarming with the National Guard, all of which are very resilient, are immune to their heads exploding from the Sledgehammer or Baseball Bat and all carry machine guns. These traits all put together mean that you'll be torn to shreds faster than you can say "I regret nothing". Oh, and all those Game Breaker melee weapons you were having so much fun using? The soldiers are either immune to them, or block them with their two-handed weapons, rendering all of those Game Breakers completely useless! Hope you can find the Axe in there, since it's the only practical melee weapon in the level!
The following levels aren't too bad in comparison, since most of them will be full of zombies, who die immediately if you inflict Your Head Asplode on them. The Dog Pound is where the game starts to ramp up again. The main enemy type in this case will be Rednecks (who are, incidentally, the same type of enemy that appeared in the Brewery). Although they will also be happy to use their two-handed weapons to block your melee strikes, they aren't as resilient as the National Guard. The real problem in this case arises from the swarms of dogs who are fast moving and hard to hit.
Then there's the final stretch before the end... the Bridge. The Bridge is mostly full of the aforementioned zombies. Not too bad, right? Except the game throws in more National Guard on top of it, as well as some crazed civilians, who all attack you on sight. As a plus, some of them are flinging around grenades, along with the bridge being bombed from time to time. Was it mentioned that explosions do huge amounts of damage? This wouldn't be too horrible, if the bridge wasn't cramped, leaving very little room to avoid the damn things. And at the end of it all, you have Mad CowMike J...
In Postal 2, you can pee on things. Peeing on people generally causes them to throw up violently, with some fairly advanced liquid physics for the game's time. In one level, the Dude gets gonorrhea, and his urine becomes green and burns when you pee, which guarantees that people you pee on will throw up in reaction. And it's possible to decapitate someone as they're vomiting, causing it to continue to spew out of their neck stump.
The cats and dogs in S&M gear near the end of Apocalypse Weekend.