Shit ton of quests, the completionist ultimate goal of clearing out the quest list. Just a shame none of the quest themselves are fun or worthwhile to do.
Lore. I think the amount of bad story design outweighs the good, but the lore goes pretty in-depth and is interesting enough to keep me invested in the game. Community. While I'm not actually interested in most of the aspects of MapleStory as a game, I enjoy how close-knit most of the community is. It's mostly due to the community's small size, but you'll recognize many familiar names cross-platform as you browse even if you don't personally know some of them.
The part where I afk in a random place and when I come back after forgetting I had maple open, one of my friends is just magically appears and afks as well.
Biggest problem with the lore, though, is the amount of shit that's been retconned and arbitrarily changed over the years. Case in point the seemingly out-of-the-blue decision around heroes of maple to declare aran's cannon gender to be female. And they never go back to update old shit with new changes.
I enjoy the mechanics of bosses, and how scaling works, as you gain gear in this game its kinda crazy how different the levels of gears get even among casual/weak players. So you always have somewhere to go, I guess anyways. I also dont like that aspect though, I feel like alot of the cool boss gimmicks in this game that reward control and have cool interactions with classes are wasted when you can just get so strong that you just solo it in 2 minutes.
My favorite part of MapleStory is the sense of pride and accomplishment I get from being able to play the game for longer than 5 minutes before disconnecting or crashing. No but really my favorite part is the onslaught of shitposts and memes that come out of the subreddit and official discord when Nexon inevitably fucks up bigtime.
If they have to retcon something to weave it into the larger world I don't really see a problem with that. It's when they decide to completely ignore the foundations and then build over them to make something worse when it's a problem. That doesn't happen very often though and Aran's gender was never set in stone anyway. Original lore is still the original lore if you ignore the shoehorned updates. "Recently" they've updated Masteria, Korean Folk Town, Kerning Square Mall, Fantasy Theme Park (the ludi one), and Omega Sector. Good Example: Florina Beach, horrible questline that is literally self-contained and makes no reference to anything else Maple related. They've closed it for quite a long time while they've claimed to rework it. Literally anything they do to this will be better than the "original lore". Bad Example: Masteria Through Time. It's like they glanced over the amazing primary story and just went "Eh, fuck it, we'll just use some of it and fuck it over by using time travel and wrong information, check out our idea instead of what it was meant to be." The reasoning behind Aran's unspecified gender is because originally, Aran was part of a group (race or village) rather than a singular hero. In the Pre-Aran in-game quests, there's a lot of talk about "The Return of the Arans" and everything is referenced to them as plural. Despite that, the original Korean teaser-site for Aran describes the Hero as the last of their people. The Hero has memory loss and doesn't know their name, so we just call the Hero by what they are, an Aran. This was back when Aran was the only revealed Hero with none of the other heroes around to remember Aran's name (doesn't explain Athena Pierce not knowing though) but I don't know if that's been changed into being their name unless they were always referenced as just the "Aran". I believe the gender was left open to not exclude what gender the actual player was (much like how the Explorer is just an Explorer, not specifically a Male Explorer). Once they started expanding on an actual story, they needed to choose how to represent the character since they would be displayed more often. I haven't looked through Aran's initial release questline itself yet and I assume it hasn't changed much, but obviously you can see now that she's been cemented into a singular female Hero, probably after they noticed how much of a sausage fest the Heroes were going to be revealed as. You can tell they had a different initial plan for the Heroes planned out due to the teaser image of the 5 heroes facing the Black Mage. Anyway, people like to reference Aran's gender as an issue but it was never specified as Male aside from the artwork, which also had Female versions even prior to Aran's release. Aran's had equal reference as both genders, they just finally decided on one for the sake of story purposes, not really out-of-the-blue or a problem as it's necessary in order to show a character. Some other characters have artwork or even videos of the opposite gender as well (Evan, Jett, Demon Slayer). Spoiler: Aran Artwork Left to right: Aran Unspecified hero wielding a bow (not Mercedes with Dual Bowguns) Unspecified hero with just fists (probably what ended up as Eunwol/Shade) Unspecified hero with a scepter (not a Shining Rod but potentially a Cane I guess) Unspecified hero with sword (due to crossguard and sheath visible) and shield. Looking back at this, it almost just seems like Aran + Explorers sans thief unless the fist/pirate guy is wielding a claw or two. I'd believe that if it wasn't always mentioned that there were 5 heroes that fought against the Black Mage.
When I was younger, the thing that kept me attracted to MS was the community of course. Keeping the game difficult in the early days made me feel like I had accomplished something when I leveled and that helped too. Over the years, I made a whole lot of friends ingame, and I ended up staying with them for that. As time went on, I tried to help out MS the best I could from the outside by joining communities and Nexon ran thinktanks. Nowadays I don't play as often as I used to. I'll play sporadically and it just doesnt feel the same as it used to. It's still a fun game, but I just don't have 1k to throw at cubes every month or two. TL;DR, the community.