Ah Garfield, a joke in every panel. 1) Crazy bow-tie, 2) the Awkward Pause Take, 3) a man with his head on the table, weeping!
Garfield's last quip confuses the issue in this otherwise stellar strip. Garfield would've believed Jon had a regular not-"big" date? Or does Jon have a date? I thought the joke was that Jon is prepared and excited for something that's not going to happen.
Anyway... this clinches it: Jon officially has a designated, iconic Ugly Outfit for Dates. It will have to be in the Index when Fantagraphics publishes The Complete Garfield.