A story that is as immersive and vast as Halo, a story so good people will come up with conspiracy theories for reasons things happened or motives for someone doing something. I've seen some Tumblr posts about Harry Potter books where people who over analyse every little detail, find a way to make it all make sense with the story. I want hidden things, like Halo's skulls that make me go search the corners of every map not because I have to, but because I WANT to. Not RNG open a chest and maybe get a skull. Every Halo game that has been released I purchased solely for the story. I always ended up playing a lot of PvP on each of them, but not before I beat the game on Easy and Heroic first. Sometimes I'd even beat it on Legendary before playing with PvP. Halo made me want to play PvE, whereas Destiny's PvE is "meh" at best at any given time.