I'm sure this has been done already in another forum but ohwell.

Which boss/es have beaten you the most/ been the most difficult to defeat.

these are mine, bare in mind when i gave these games to my brother to play he beat them all on his first try >.>

KH1: While these were hard it didnt help that i had to watch the movie every time i lost.

.Stealth Sneak. if it wasnt the lizard killing me it was Clayton shooting me when i had no health.

.Rikku (in Hollow Bastion)

.1st two rounds with Ansem, the third seemed alot easier.

KH2:

.Xigbar. it didnt help that i didnt want to beat him, let alone fight him.

.Xaldin

Eyerything else took two-three tries max.

Days:
Leechgrave and Xion.