This is mostly about the Madhouse, but it applies to too many events in Maple, that have an element of RNG and limited attempts. So, also things like the Dark Lords of Darkness, Hunter's Club, SAO (although that one had a paid element), and so on.
An event needs to have a way to make sure everybody wins, provided they try hard enough.
Examples for the Madhouse event:
- Allow going back in when reaching the Escape room, without using up another pass. It's still possible to never find a certain page, even when allowed to wander the Madhouse eternally, but it gets vanishingly unlikely.
- Make it possible to buy any diary page you are missing by paying some (large) number of coins. This could either be the Vending Machine NPC, or it could be some new shady NPC (like a greedy Orderly) that only appears after you have cleared X amount of rooms.
- Make the chance of getting a page out of the appropriate reactor go up with the number of attempts you make, until it reaches 100% or until you get the page. So, if the chance of a Test Tube dropping Page 2 starts out at 5%, then every time you activate a Test Tube it will go up by another 5%, until after 20 Test Tubes you are assured of getting that page. Once you get the page the chance resets to 5% and stays there.
I'm sure other methods can be thought of. The important part is, again: make sure everyone who makes a sincere effort can complete the event.
Making us work hard for our rewards is fine. But making us work hard and then still fail due to random chance, is frustrating, enraging, and unfair. Real Life does that, but we play games to escape the frustrations of real life, not to get more of them.