This is the latest in a series of strips about Jeremy and Sarah: Jeremy seems not to be listening to Sarah at all (and Jeremy’s father is presented as doing the same to Jeremy’s mother), and now, when Jeremy responds, it’s in monosyllables — he’s speaking, but not communicating.
That gives us two stereotypes at once: genderspeak and teenspeak. Males don’t listen, males are uncommunicative (especially when talking to females), and the teen stereotypes are for “laconic guys and gabby guys”.
In the strip above, Jeremy finally produces a minimally non-monosyllabic response. I doubt that it will satisfy Sarah.