You've never had disease? The earth esper uses that alot. It reduces your current and max hp at the same time when you take damage.
I...don't think I ever got that... <.<
The mines near the beginning, just after you get Fran, Balthier and,, later, Basch. At that time, levelling up was harder. It took me 2 - 3 hours to get past those. Haha. The others have been simple enough 'cause I've made sure I'm at a good level.
The only part in the mines that gave me trouble is that one room that branches off and when you flip the switch you have to fight off about 6 flans. That was a terrible since I was already low on MP from dealing with undeads and that stupid dino earlier down the tracks.