I'd forgotten about that. Circumstance, enhancement, synergy, flanking, competence, concealment, dodge, armour, natural armour, uuurrrggh.
I ran a 3.5e game that faded out at 15th level, and even though my players were never hardcore minmaxers or particularly keen on playing the layered buff game, I still remember it with unfondness.
I could still be convinced to play/DM a 3.5e game if the group absolutely refused to consider 5e, but I wouldn't take it above 7th-9th level or so. The maths hasn't collapsed under its own weight by that stage.
Ha! this reminds me of an experience I had with a group I met off a bulletin board in the game store. It was a homebrew setting, and I was playing a Cleric of Ehlonna, with the Sun and Good domains. This encounter took place at sea, we spotted an enemy ship full of meanies and nasties closing us fast. The DM gave us 5 rounds to prepare for the fight to come.
That was his first mistake.
I'd never really gotten the chance to buff up like this, and so I went for it. Divine Favor, Divine power, Bless, I forget what else- but I ended up being a melee juggernaught, lol. The resulting fight was considerably easier than he'd intended... He was a good DM, just new to 3E- and underestimated how much a spellcaster could power up, if given the time to prepare.
Later on, in the adventure, with our feet on dry land again. We ran into a group of ghouls, in what was most certainly supposed to be a tough, climactic encounter.
Mistake #2. Forgetting about my cleric's Sun domain power: Greater turning.
POOF!! I rolled high, he rolled low. All of the ghouls turned to dust... Fight over as soon as it began, lol.
He wasn't too happy, but took it like a good sport, and remembered for next time.
It was one of the big take-away DM lessons for 3E: Control the tempo. Giving players too much warning and lots of time to prepare, can result in some serious curb stompings. Also, attrition is your friend! As is letting your NPC's/Monsters use their brains for more than just a place to rest their hat.
AND, Bone up on your player's characters. Know about special abilities, how they work; what goodies they have; which spells they've prepared etc. Helps avoid mid game surprises, and helps you design encounters and challenges that actually test your party. Lull em into a false sense of security with encounters with weaker, dumber minions/ meat shields. Then introduce them to the smart ones! That OH SHI$!!! look in their eyes is priceless!!
"Hey, hobgoblins are supposed to be a disciplined, martial race, skilled in the art of war, right? Well, you waded through all their neighbors (aka burgler alarms), killed a few hobgob guards- then left. What do you think they were doing while you returned to town for a cold one and some supplies??" (that was one REALLY fun session for me! )
It's all good- my players in that campaign included my regular DM- who has pulled every dirty trick in the book on us in the past. I just said: " You taught me well, didn't you?"