After playing Persona 3: FES, any boss in Persona 3: Portable. The removal of party members getting tired and leaving in the middle of Tartarus, the addition of the ability to resume at the last floor you were on, the Guard command and the option to manually control your party members pretty much breaks everything that made the original Persona 3 (and FES) difficult. The game practically throws awesome SP healing items at you, making it absurdly easier than Persona 4, which I found easy to begin with, if you're not apprehensive about using items. I find myself hoarding Soma, which are like Megalixers, and end up with, like, 10 of them by the end of the game, and at most one of them will ever see any use.
To give an example from the early game, the Change Relic spams wind attacks, which one of your (required, at this point) party members is weak to. He takes a lot of damage from it and gives the Change Relic extra turns because of the way weaknesses work. In addition, your party may be tired, and when they're tired, you can't go back to the first floor of Tartarus to heal because then your tired party members will leave you. This boss is sometimes considered one of the hardest in P3:FES. However, guarding in P3P nullifies a character's weakness. The character in question has no real support skills, and at this point his damage output isn't much different from anyone else's, so you can just have him guard every turn and soak up damage. You don't have to worry about anyone getting tired, either; in P3P, it only takes effect when you leave for the night.
