The first two panels in this Blondie, as in many Sunday strips, are throw-away panels so newspapers can excise them to save space while still maintaining the cohesion of the comic. My newspaper, however, decided to leave the first panel in while taking the second panel out. The result being that I thought the comic was about Dagwood being sad about empty vending machines (despite his earlier facade of nonchalance) when it was in fact about him trying to decide whether he wanted pizza or corned beef for dinner. I think.
As it turns out, it's not funny either way.