Ah, but that makes it a plot arc! They will be building from it, and it's a connector, not an unfinished loose thread. Like the random appearances of Rose throughout the season.

As far as Coupling, I actually severely dislike those situations, too, and can't stand run of the mill sitcoms (or even romantic comedies). Coupling overcame that objection entirely by means of sufficient quirk-level of characters, and good writing. The only other relationship sitcom that has measured up for me thus far has been How I Met Your Mother.