You should try out some SMT. I just recently found and started up a game of Nocturne, lookin forward to gettin all the possible goodies in the game. DDS1&2 and the recent Devil Summoner title left me with the utmost respect for both the line of games and in particular Kaneko Kazuma (artist) and Shoji Meguro (oh lord yes the music, why no remixes at ocr..=(..why).
For some reason in DDS1 I had a rough time with Dragon Vasuki at the bottom of the final dungeon tower. While my ice drains were constantly up, she kept getting lucky with random panics on my party members which ruined the rhythm of damage output and keeping shields up.
In DDS2 I had a really rough time with Asura Ravana at the end of the fifth layer of the sun. He was just so damn strong, and the random -dyne level nukes kept disrupting my plan of having Phys drain up. Surprisingly Yaksa Meganada and the final boss were a breeze after that.
I'm hoping after I finish with Nocturne I plan on goin through DDS1 & 2 again, but this time attempting the "demi fiend" optional fight in DDS1 since I'll be on a new cycle. Now the demi-fiend I have heard is just impossible...
Also, a rough spot in a game in general, bosses and random encounters included, was the Cave of Trials in post game SO2. I only ever got to level 7 in it, my characters were all around lvl 140 or so and all hp/mp/skills maxed so most of my progress at that point was luck.