"Know your character well", it was said.
"I don't want any long delays breaking up combat as you look stuff up", it was said.
The
very first turn, and our loud player with the corrective memory ground everything to a standstill with his complete lack of understanding regarding his character, the houserules of the game, and basic addition. Surprising absolutely no one.
Even after a long guided talk through his Paladin/Hexlock mechanics and how they work together, he
still doesn't understand how half the character works and is therefore playing it at vastly reduced capacity (he thinks Eldritch Smite adds a single 1d8, regardless of slot level, and believes that he can't use Divine Smite anymore since he has "swapped it out for" Eldritch). At this point though, we've just kind of quietly agreed to go along with it in order to keep the game moving.
Also I have a better command of what his +tohit and save DCs are than he does. So there were multiple occasions where he was asked to provide one or the other, started scrolling through his character sheet, and I just answered.
It was still an interesting session, certainly! I put in the last hit on a stone golem by slapping it with a weapon that cannot damage it, an umber hulk landed a crit on me (remember the house rule about treating bonus crit dice as though they rolled max? Yeah) that ended up dealing a total of 3 damage, and said hulk ended up confusing me so I wound up taking a 31hp chunk out of Mr. Loudmouth who was rolling around on the floor being effective at the time.
Me: "I'm assuming a 27 hits?"
Him: "I'll use my reaction to cast Shield!"
Other player: "...you have 20 AC"
Him: "Yeah, and now I cast Shield!"
Other player: "Shield only gives 5 AC, that's 25 total. He still hits"
Him: "Whuh...uh?"
DM: "Well, now you've spent a slot on learning about how your spells work. Moving on"
The session wrapped up with me dangling over a precipice in the loving arms of a roper, the conga line of giant spiders coming into view, the drow party mostly vanished into the shadows (except the mage, who is currently snoozing on some minecart tracks), and what looked kinda like an ankheg coming out of the ceiling. Also the floor mimic woke up.
Now,
RAW, I could actually just wriggle out from the roper and survive the plunge easily, because 5e. But the DM doesn't really like the idea of fall damage capping out at 20d6, and I'm inclined to agree