I actually got into KH by playing number 2 first. I remember, I got so frustrated by 1 boss fight, the constant calls of "Dance Water Dance" before I died that I stopped playing the game made me stop playing for about 5 months. After my 14th birthday, I picked it up again and beat that boss first try and it was probably my happiest moment so far.
Then my memory card got corrupted and I had to save up, get a new card and play it all over again! I never took a break again though, I played that game all the way through and it was, and still is, my favorite game of all time