On to the strip itself:
Panel 1: We see John saying goodbye to Jean as he leaves the office for the evening.
Panel 2: He's in a good mood so he sings along with the Oldies station on the drive home.
Panel 3: He's in such a good mood, as a matter of fact, he decides to stop at the florists to buy Elly a potted plant to show her how much he cares for her. Ain't that nice? Too bad he's giving the gift of flowers to someone who doesn't respond to nice gestures.
Panel 4: He then presents her with the potted plant....
Panel 5:...only to be asked what he did wrong. See what I mean?
Hypothesis: John married a woman incapable of feeling happiness. Anthony wants to marry a woman like Elly. He will. Also, Elly will start off ranting about all the times he's disappointed her in the past but get off topic as we lurch uneasily into another flashback.
ETA: Failing that, howtheduck is right and we've just seen the beginning of the "Retirement of John Patterson" story arc.
ETA2: My computer is acting up a bit so it may become necessary for someone else to set up a thread or two.