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.
The music for the LBP 2 announcement trailer,Sleepyhead by Passion Pit. Also an Ear Worm. Though, they didn't use the entire song, they just used the part that most people know, the 'Fairy Chanting' bits that are really only in parts of that song. Did you even know it had lyrics?
"Sleepyhead" is also used during the credits.
"Whoever Brings the Night" by Nightwish, used for the first and fourth boss fights.
"Vision One" by Royksopp. The instrumental version on the game is pretty awesome, but the original version actually has cold and depressing lyrics to accommodate it.
Fridge Brilliance: Uncle Jalapeno, the Mexican character, has a lowrider in the first America level.
Good Bad Bug: LittleBigPlanet has a huge range of Good Bad Bugs! One of the most spectacular is the '3D' bug, which lets players build with 50 more layers (although it's really tricky to use, but the makes the level amazingly beautiful if used correctly!) and is still not fixed. Another, which HAS been fixed is the constipated sackboy where the player chooses the 'reset button' holding it down and then pressing START the START Menu would block the screen so only your friends could see the paused player. The Glowing Sackboy glitch let the player glow with a sackboy skeleton, going well with the zombie-sack knit.
Most Wonderful Sound: Stephen Fry's narration. As Yahtzee described it as: "[feeling] like a velvet finger soaked in warm honey being gently worked around your earhole. I SAID EARHOLE!"
Nightmare Fuel: The series actually has quite a bit of this; some of it's subtle... but there are other things that aren't, such as the Ego Stickers you can obtain in LBP 2.
The Vita game RUNS on this. The final world in particular is pretty terrifying, with many, many jump scares and a very dark atmosphere.
Scrappy Mechanic: The '3-planes' format can be very easy to stumble with, especially when you try and go up stairs or ramps and keep. Jumping. Behind them.
And the automatic plane-selector seems to hate sackboy, even overriding your manual changes at the worst possible moments. Like falling 'behind' a safe platform and onto an insta-kill floor. Or when running along you smack into a wall that only exists on ONE plane. Or moving sackboy to be squished by something that could easily be sidestepped. Etc. etc.
Good Bad Bugs: Many relatively harmless glitches have been discovered and used by creative players:
The 3D Glitch: Allows you to build extra layers both in front of and behind the standard layers. However, player movement is still restricted to the main 3 layers. Possibly the most-used and most famous glitch of LittleBigPlanet.
Anti-Color: A fun little glitch that made certain kinds of Sponge look like Glass while still keeping the stitches. Since Glass is invisible behind other pieces of Glass, this left only the stitches visible. Fixed in Cornish Yarg, though the objects themselves still work; you just can't create them anymore.
Material Properties Glitch: By changing an object into Horrible Gas, using the Material Changer, and delethalizing the object, you could make an object with the physical properties of the first material, while having the texture of the second. Could be used to make things like Floaty Metal, movable Dark Matter, etc. Fixed, but pre-existing "changed" objects still work.
Similarly, doing this on the PSP without delethalizing it allows for the material's texture to be transferred into gas form.
Non-Lethal Spikes: It is possible to smash the lethal part of a spike object without destroying the whole object, though it is hard to do. Still works, but not used often.
Gravity Glitch: Very few people know how it works. It involves Pistons, and that's about all that's commonly known.
There's another, simpler version of this glitch that only affects individual platforms, allowing the gravity to change from jump to jump.
Hype Aversion: So anticipated, its fans praised it to the point of annoyance before it was released.
Good Bad Bugs: The Robobun and the Mechapup can "climb" up walls indefinitely if a player riding either one pushes against a wall while mashing the jump button. This makes it possible to bypass many obstacles in certain levels of Avalon and The Cosmos.
Scrappy Mechanic: The Grappler. Dear God the Grappler. If you try to swing back and forth to gather momentum, you will end up reeling yourself up into whatever you're hooked onto 95% of the time.
That One Level: While there's nothing on the level of The Bunker, there are a few that are infuriating to ace, especially two-part levels.
Of note: Full Metal Rabbit in The Cosmos. The first part of the level pits the player against several guard towers with bad guys tossing impact explosives at the player. To proceed, these impact explosives must be tossed back at the towers to destroy them. Later on, there are several platforms over fiery pits; each platform has a bad guy shooting flamethrowers at regular intervals. Mess up the timing on one of them and you're dead, spoiling your Ace run. The second part has the player riding the Robobun, which has unforgiving Jump Physics, extremely floaty movement, and no attack capabilities except for a power stomp. This entire section is filled with enemies that can One-Hit KO you with blasts. Good luck in trying to learn the timing of the final three turrets before the goal...
Uncanny Valley: Victoria von Bathysphere has a rather realistic organic-looking head and face, especially in comparison to the rest of the characters. Combine this with her super-deformed proportions and robotic body, and players might find her appearance little unsettling at first.
YMMV Little Big Planet Karting Tropes
That One Boss: The Firepede fight at the end of Eve's Asylum. It has multiple weak spots which, when destroyed, leaves behind a trail of instant-kill slime. Destroying these weak spots at the wrong time will usually leave the player no choice but to die.