Clean, comfortable, quiet room.
Easily accessible transportation. (Not necessarily on an ECV, since I rent one @ the parks, but not MILES from my room to the bus stop, or being able to get to boats/monorail, etc. fairly easily. I will also say that the wheelchair/ECV rental areas in the parks seem like a LOOOOONG walk from the buses some days!!!)
Good, friendly CM interaction.
Fellow guests with good manners. Or at lest as low crowds as I can possibly get these days, to be able to navigate the rude ones better.
ECV's being available when and where I need them, and not going like total snails.
Good, freshly prepared food, at a price I feel is reasonable for what's offered.
Warmish is okay - but NOT hot, and low humidity.
LOVE the Food & Wine Festival.
Good serendipity experiences.
Getting "the feels" and reliving great times and memories doing something sweetly nostalgic to me.
Having that "everything is going to be okay", and "I'm on VACATION!" feeling.
Being able to suspend my stress and belief in the "outside" world and having fantastical things take me away to a better mental space.
Those are general things that would/have made my visits magical. There would be WAY too many to list shows/attractions, but I'm sure I'll enjoy reading other's responses.