The best dinner party occurs in Portrait of the Artist as a Young Man. Young Stephen is at the table when a viscous argument about Irish politics breaks out between his father and aunt. Even though I did not understand the context, that dining room table fight absolutely bolted me to the floor. And, really, Joyce is counting on you not precisely to get it, because that disorientation is part of the reader feeling Stephen's growing panic, allowing the politics to stand in for other, more simmering resentments.
"Best" is maybe an awkward descriptor for this dinner party. Certainly there are many other dinner parties I would rather attend, like Bilbo and the dwarves at the start of The Hobbit, or even Mrs Dalloway's tragically interrupted party at the end of her eponymous novel. But I don't know. Joyce's domestic battle was so raw, so complicated, packing in all of this subtext in a few nasty lines, and simultaneously casting the reader as Stephen whether you want to be or not. I've been at that table too. I've had those fights.
My first instinct was to pick The Red Wedding from GRRM's Storm of Swords as the best dinner party, just for the lulz. But George Martin's got nothing on Joyce in terms of bloodbath and betrayal. Joyce has less literal bloodbath, but that doesn't mean you're not bleeding. Leaving the table with just a slit throat would be an improvement sometimes. Boo yah. Erin go bragh.