Less friendly cast members, a dirtier park, Park layout is harder to navigate (lots of dead ends), general park design (MGM may be a mess but the other three have stuck to a visual theme, whereas California Adventure has not), security is a much less enjoyable experience, downtown Disney, no golf, no minigolf, no boat rentals, no Boardwalk, no water parks, far fewer dining options, far less to do overall, the castle, thunder mountain doesn't help pass kidney stones, air quality, darkness inside Space Mountain (also the ride in general), killing poor Mr Toad (lucky for them).