Delusion, Not Ignorance, Blocks Understanding

 Everything is easy to understand. Basically this is due to the atomic nature of reality. Anything hard can be broken down into its component parts until you get parts small enough they can be understood individually. This is why, if your brain isn't crippled or maimed, you can learn anything - IQ only determines how long it takes. How small the atomic compounds have to be, how long it takes to package the compounds into combinable packages.

 If something seems fundamentally hard to understand it's because you're delusional. "But if [truth] obtains, that would disprove [superstitious nonsense]!" It will be impossible for you to understand that truth if you're unwilling to discard the delusion. "How can [truth] and [balls-tripping hallucination] be true at the same time?!?" Deeply and profoundly...or you can drop the delusion.

 The best part is that usually the delusioner refuses to admit the delusion is even relevant. It won't occur to them to mention it. My fake quotes are wildly over-optimistic. Likewise enumerating the assumptions is, like, work, and they'll refuse to do it. Try to change the subject.

 You can persuade a delusioner to believe in the truth...provided you have the advanced telepathy required to figure out what delusion you need to attack. And you have a bigger stick than whoever implanted the delusion in the first place, so they're more afraid of you than they are of losing the delusion.

 

 Rift Wizard 2: "Eye spells are weak!" Uh, there's an eye summon, you have to use the eye summon, not just the enchantments. It increases your power by sixfold or more. It's weird you can even win without it.
 If you have any respect for their intelligence it will never occur to you this might be a problem. There are four eye enchantments which are all variants of each other (of fire, of ice, of lightning, of rage) and one eye summon, for a grand total of five total spells. They have to try an eye build while overlooking 20% of all eye spells, and 100% of non-clone spells, to get their result. 
 Secondly, there's an open/tight world problem. Before you get the summon, you want tight levels so you focus your eye attacks on the few visible enemies rather than evenly distributing your damage. Kill quickly rather than as slowly as possible, lol. The eye summons are immobile and can't chase down stragglers, so after that you want open levels so the enemies aren't protected from their attacks. (Ideally you want them to see exactly as many enemies as they'll kill before they expire, and the rest hidden.)
 They're assuming you don't need the summon, and you should use open levels (because long range) and they will never mention either of these. You have to pry it out with a crowbar, and they won't let you get anywhere near them with a crowbar.
 Most delusion is like this. In this case the stick is their own ego. They want to be [[right]] about eye spells in a tiny niche videogame - like a respectable adult, lol - far more than they want to be good at eye builds, so they'll make shit up to [disprove] any new information. The delusion is basically the point.

 Darkest Dungeon 2: "The relationship system is so bad!" It turns out they let their guys spike up to like 8 stress instead of keeping them at 3 or below. "Wow meltdowns are so punishing." Uh, try, like, not not-healing stress, you fucking morons. Again if you have any respect for their intelligence you'll never realize it doesn't occur to them to deal with stress by using stress healing more often. Though I'm not 100% sure I've got the right problem in this case. There might be other batshit nonsense they're taking for granted. If you try to get them to describe the problem in enough detail, you'll find they're not verbal enough to manage it. Words too hard, many difficult, wow. They can't do it by copying something they saw their mom do...
 This uncertainty regarding the delusion illustrates the comical level of telepathy you need to work out what the fuck is wrong with their brains and persuade them to stop jackhammering themselves in the knee. 

 DD1: "I'm taking a lot of stress damage. There are enemies doing stress damage, and enemies not doing stress damage. Wat do?" Uh, maybe kill the ones doing stress damage, so they can't do it? What kind of crazy do you make your brain with if you can't think of this yourself?
 Games, and society, are largely balanced around brain-holes of roughly this size.

 If you have a big stick you might as well command them to mindlessly obey you. "Screen share your DD2 play." "Okay, now take a jester. Now cast inspiring tune." Make 'em learn by rote. Understanding is a stupid veblenian hobby. Revenge is sour: if they were prone to believing true things they wouldn't have accepted a delusion complex in the first place.