Sample:
DM: Oooh, do you know who I bumped into in town the other day? Janet Smith.
Me: Who?
DM: Janet Smith, you remember, who used to go to church with Grandma.
Me: blank stare
DM: proceeds to give me full details of X thing that happened to Janet Smith recently despite the fact I have literally no idea who this person is
Another sample:
Unfamiliar car parks in street
DF: <leaps up like meerkat and rushes to window> who does that belong to then? Never seen that car before?
cue him and DM spending the next hour discussing the owner of the car and who it might belong to