I got a really talkative PUG in my last two games. Does not happen often.
While waiting in the lobby (me, the talking PUG, two others without consumables (<A>, <B>)):
"You know it is considered rude to play gold and not have any consumables on. I'm talking to <A> and <B>." (Or something similar.)
<B> puts consumables on, <A> leaves. ==> "Thank you, <B>."
Another PUG (<C>) without consumables joins . . .
FB Hydra/Cerberus/Gold
Wave 1:
I die
, <C> revives me, <C> dies, I revive <C>.
Short time later <C> dies again. ==> "Yeah, <C> thanks for playing."
Wave 3: Escort
<C> sticks to the drone as do I and the talking PUG, <B> stays in the same place and tries to kill stuff.
We are almost done ==> "<B>, you wanna help out or are you just playing by yourself? Screw the team --- is that the problem? I get it."
"<B>, you need to help with the objectives, don't be an a**hole!" 
(Edit: <B> actually did the next Objective.)
Wave 5: Atlas on the roof . . . and the BS continues (unable to charge etc.).
Sadly there was no more talking to cheer me up. 
(Only a wave 8 Missile Killstreak with 8 enemies.)
After extraction without <B>: <B> and <C> leave.
AIU (<D>) with Venom Shotgun and Explosive Rounds joins.
"Are Explosive rounds any good on the Venom?"
<D>: <silence>
"It's a secret I guess." (Or something similar.)
He talked some more, but I can't remember what he said.
This PUG seemed to take the game quite seriously. Thanks to his talking the games were at least a bit more enjoyable. 