The only problem with this particular topic for me is... I don;t want to spoil any game ever lol. Spoiling a game fro someone, kinda ruins the experience or, possibly... can dampen it in a way that is not good. As a result, I don;t like to spoil anything, especially not Story Driven RPGs ((Half of playing is seeing the story... spoiling it is just not cool.))
I will use some games as specific points.
Dark Souls, and other Souls games. Hard games... ((I say that with utter contempt by the way... the Souls games are not actually hard games, they are games with steep penalties for messing up yes, but that does not make them hard.)) to a point part of the fun is figuring out the challenges they lay before you, and learning what the game is trying to tell you. Learning to fight certain enemies, finding out enemy placement in the current section you are on, what those enemies aggro range is etc, is all part of the layers. Learning all of this and how to go with an area without a scratch is part of the game, and part of its draw. Telling someone exactly what to do, or how to do it really ruins the experience. You rob them of learning themselves, or that feeling of when they finally beat that area or boss they stuck on. Not much compares to that feeling, of finally figuring out to to beat that boss after 15 attempts and laughing as he lay a newly minted corpse on the ground as you steal his soul from his cold lifeless husk. ((huh... that got a bit dark...)). Now, I do understand some things could get frustrating to the point where somebody isn't having fun anymore. That would probably be the only time I personally would give them any hints.
As Above, Plots. More specifically games that rely on their plots. If a game has a significant chuck of its content in its storyline I do not want to spoil annnnnny of it, even somewhat more minor details. While I do believe some moments hold up even if a player knows prior... it still makes them more flat when they do get to that point themselves. What good is the big bad reveal if they already knew it? ((Answer is... not nearly as effective.)). I personally don't like revealing side info either, as I believe people that would want to find already did, or that if they want to know one should find it them self. Looking for that is the reward in and of itself. I know people technically would say that isn;t true with how easy it is to get info on the internet these days etc, but I still believe it is very much not something that should be lol.
If you want some specific examples I suppose I could list a few with some small examples.
Dragon Age: Origins: A stellar RPG that some say was the Spiritual Successor to The old Balder's Gate games and to things like Neverwinter Knights. It is a game I feel starts off a bit slow, but once it gets rolling... man does it not stop. While there is a few spotty bits here and there... it matters little when you finally get to the end of your journey, where everything just comes together in one final crash.
The Banner Saga: Probably not a game many people have played. But it is a interesting Viking Epic inspired Tactical RPG ((much like Fire Emblem)), mixed with a bit of an Oregon Trail like traveling system. The story however, is what drives the game as you watch the Journey of 2 different Parties. ((who at some point converge.)) There are some choices t be made along the way, that might not affect the overall outcome much, but they really do affect your journey to get there.It is a game about the Journey, and that Journey is good enough to relive a few times.
Any Souls game ((Demon Souls, Dark Souls, Bloodborne yadda yadda.)): I already explained up above, but I certainly would not spoil these games. I had a genuinely good time learning the game, and becoming wise to its tricks. That feeling of learning how to outsmart the game.. feels so good. And it feels equally as good when it swats you down yet again, and you need to reevaluate your approach, Not to mention how much things liek your gear change the play experience. It is certainly a game one should experience themselves blind once, jsut to get that satisfaction of learning it lol.
Shadow of the Colossus: I won't even go into why I believe this one... I feel even that... spoils too much. This game needs to be played to be truly experienced, My Lips... are sealed.
Final Fantasy 10: Hey, I am a weirdo that actually likes this Final Fantasy, and is crazy enough to say it is his favourite one. But yea, will I don;t think this game has aged well in some respects. ((My lord is the voice acting bad sometimes...that laughing scene...why... WHY?.... WHY!!?!?!!??!!?!?)), and while i am not too fond of the ending, I loved playing through it, the story to me... is great.
Final Fantasy 6 ((or 3 for those Old School Guys.)): ANother FF game... weird huh? I guess I jsut like them... and yea... they are bloomin' old at this point... but whatever XD. This one is much for the same reasons as above. The Journey is just so enjoyable to go through. And each character ((there are 14 I believe.)) other than the 2 Seeeecret ones feel so fleshed out and great. This is a soft spoiler, but this is one of those games... that nearly tricks you, it makes you think you have come up to the final encounter... only to find you have another whole half of the game left. Even though I had an inkling of what was to come ((I didn't know the exact twist, but I knew something was going to happen.))... it still felt so impactful to me, because the pacing of the game... makes you feel that way, and to find what you do waiting for you at that point instead, dang that is a surprise I still can;t get out of my head becuase it was just like... "What the...? NO!!! WHAT THE HECK?". THe first time... it just is like... how... why? It feels like you were robbed almost, and then... then it is time for revenge XD.