A coworker took time off to have surgery. When he came back to work, they got him this cake.
Appreciating anything more specific...than their existence is harassment. Let's be honest: if you worked in that office, this would probably be the most you could say about the subject, because you really only noticed that Bob was gone when you couldn't take a Friday off because you had to finish some of his work. You can't make any jokes about how you're not looking forward to his B.O. coming back to work, because you'll get fired.
So you agree on a bland statement that everyone can get behind, because that's how corporations work. "Not Dead is Super Good!"