I want to read something different and I haven't read a novel with a crazy mc. The mc behaviour does not need to make sense.
https://royalroadl.com/fiction/7599/how-to-tame-your-princess the mc is pretty weird and its really funny how he reacts to things with the voice in his head to support him
how about The Strongest System? the MC is so shameless, he is borderline crazy, the story is funny AF tho theres some serious part as well, so far it is more focused on the comedy most of the time while the plot is steadily progressing the Log of Crazy Lich, although the MC is not really crazy, I can't say he is sane, the comedy is great while the plot is so grand yet fun, the writing is great, theres no repeating nonsense like most CN novel, although someitmes infodump is a bit overwhelming, great story sadly the translation esp of the newest one is rather bad The Silly Alchemist, the MC is half idiot cuz of plot, idk how it is on later chapter but early 30 chapter is the MC reborn but incomplete, so he is an idiot, not really crazy but not sane either Summoned Slaughterer, the MC is psycho, you can say he is crazy about killing, yet quite sane about anything else, I personally like it but not few people disagree, they cant handle the madness Dungeon Defense, the MC is psycho, definitely not sane, some could say that he is crazy, it is an epic novel highly recomended I think I know few more crazy/make no sense yet good novel but I totally forgot the title ;/
I can think of Lightning Empress Maid and The Silly Alchemist, but they aren’t crazy, just have unusual thought processes. I’d also recommend The Godking’s Legacy and The Blue Mage Raised by Dragons from RoyalRoadL.
Insania Online on RRL. The MC is the type who, in his free time, goes "Sanity? THIS IS... actually no, we have no repercussions here, so I'm just going to see if I can... WHO JUST KICKED ME OFF OF THAT TOWER! I WANTED TO JUMP, DAMN IT!". Downside, the Author has been taking a break, so updates are rather sporadic right now. Short introduction to the plot: A new Virtual Reality game came out, called Insania Online, which apparently allows the player to play however they want. It's the first full-immersion Virtual Reality game ever (aka, Virtual Reality like Ark, Moonlight Sculpture, Sword Art Online, etc, where everything looks and feels like real life). The MC was playing Monster Hunter when he saw the ad for it, and went "I want to play THAT like how I play THIS". Which is exactly what he sets out to do. Let's watch in entertainment as our MC goes about doing so, both before and after he surprises Insania's God of Chaos with his unpredictability. Oh, and, of course, as this nice and friendly person makes a reputation as being the most terrifying and monstrous individual among the player base, all while being completely ignorant of the fact that he's becoming the monstrous ghost-story of Insania Online's Playerbase, even without picking a fight with a single other player who didn't have it coming to them (mostly a very specific player who plays a bandit or bandit equivalent).
I second this ! don't get fooled by the title, there is a princess in the story but she's REALLY not what you might imagine lol ... Ever read anything as crasy and rational as this... lol I even question the sanity of the author to be able to write something like lol
Dao of Magic from RRL. MC does things just because lol And I like how he combines science and cultivation.