At one point in Epiphany, Rosa has to make a flying leap off the top of a dumpster to reach a ladder. The game gives you a long list of techniques she can try, ranging from "take a running start" to "pray". The correct solution is to melt the snow on the dumpster first, but you're probably gonna fall on your ass. A lot.
Joey:[After missing once] Maybe you should leave the flying to the guy who can, you know, actually fly? Joey:[Second time] Just saying. If it hurts, maybe you should stop doing it. Joey:[Third time]Not saying a word. Not one word. Joey:[Fourth time] I honestly can't look anymore.
Also from Epiphany, we have the scene where Joey is given the task to infiltrate the Police Station for the first time. The banter between Rosa and Detective Durkin is priceless.
When dealing with the ghost on the boat in Deception, Joey learns the hard way that it's possible for him to get shot. There's an achievement for only getting shot once, but there's also dialogue for ten more bullets.
After Joey charms a ghost in ''Deception," she proceeds to make out with him several times. Rosa's response: Death Glare. Joey's response: a shit-eating grin.
Immediately followed by Rosa and Joey debating whether or not he can have sex as a ghost.
Joey's snarky comments on being unable to directly interact with the environment are always good for a laugh.
"Boy, if I could touch it, that would sure be great." "Give me just a second, I'm gonna add that to my list of Things I Cannot Touch." "There's a reason I keep my hands in my pockets. There's less disappointment that way." "Must I define 'immaterial'?" "I just can't come to grips with it." "Does it want a hug?"
Epiphany: Madeline explains to Rosa that, as a spirit guide, she is obliged to follow her host's wishes. Rosa immediately tries this on Joey, who cuts her off with a stern "NO!"
Convergence: Joey getting utterly fed up with Frank Lyons' constant split-personality gibbering and saying it's the first time he's been left completely speechless.
From commentaries and other meta:
The original commentary track for Legacy contains a segment titled "I hate dog leashes". It's a five minute long rant about how difficult it was to program Moti's leash and how much he wants to throw it into the sun. And then the "Five Years Later" commentary reveals that he had to rewrite that entire script for the Steam release.
In Epiphany, Dave Gilbert explains how he came up with the name "Vantini" for the bar.
"I looked out the window of a café and saw a van. That's how the creative process works, folks."
The blooper reels in Convergence:
Rosa: Joey? Am I dead? Did she kill me?! Joey: I... don't know. Rosa:[Corpsing] "I don't know". Well what good are you, Joey? Ya dumb dead fuck.
Abe [Joey]: "And maybe pigs can fly." ...Let me try something else there. "And maybe you'll start dating."