I think it's because when I was young, EPCOT didn't have much for me, so we would typically start there because it was a park we didn't always spend a full day in, and we could take things slowly if we were tired and just meander around without having to knock a bunch of rides off the list. And also, it would have been my least favourite park as a kid, so it was almost like we were getting it out of the way and saving the best stuff for later to keep the anticipation alive. But now that I'm older, I LOVE EPCOT, so going there feels really exciting, coupled with the nostalgia of starting vacations there as a kid.