Hollow Bastion for me, i love all the contraptions and the castle it self, it was funner in kh1 than in kh2 cuz in kh1 u got to go in the castle in kh2 u only go in the basement.
Hallow Bastion in KH1 was the bane of my existence. Seriously. I had the step-by-step strategy guide, and somehow (my first time through) I would still manage to get lost and have to start all over...I hated how easy it was to fall from the high places.
Then (my first time through) I gave up for like a month because it made me so angry and then my PS2 was stolen when my house was broken into (along with all my games except for Kingdom Hearts, which to this day makes me wonder.) I got my PS2 back, along with all my games (except FFX) EXCEPT my memory card was never recovered. So I got to start over, soo depressing, but then I beat Hallow Bastion so, yeah. Ha. That's my fun little story about why I used to hate Hallow Bastion. The end.