The nostalgia. Though, I usually only play for 1-2 months and take a huge break again to then return again. There really isn't a lot to do in the game except collect equipment or level a new character. Crafting is completely useless considering everything is so expensive, and it won't ever be useful in the end game. The only use is glamour, but spending 900k+ on mats to craft stuff is a bit, meeeh.