That was a very common sales trick back in the day, particularly with Superman comics. Because everyone knew
what a decent, wholesome, all-around-good-guy that ol' Supes was, the creators loved coming up with covers like this that showed him acting like a complete dick to friends and loved ones (particularly Jimmy Olsen, Lois Lane and Batman -- then again, Batman probably deserved it anyway
) and so hope that the potential reader would go: "GREAT KRYPTON! How can this BE?! I've got to read this comic! Even if I don't eat tonight, I'VE GOT TO HAVE THAT COMIC!"
And then, in the story itself, we'd get the scene in context and discover how Superman wasn't actually
being mean; it was all for their own good/part of an arranged scheme in order to catch a supervillain.
Of course, in most cases the context wasn't anywhere near as fun or interesting as the cover was.
Awww, who cares. This is a great site anyway! *goes to look at more comics about Jimmy Olsen in the most bizarre situations*