Darth Vader Coffee Mug

It's labelled someone who insists that life is empty when not fully lived.

This is clearly labeled by a pessimist. They want the can emptied out when half full because it will surely be dirtier to pick up a full can spilled over.

Unless you are playing at the wording of the label, then my answer is that it was labeled by a pessimist who thinks that a half full can of garbage is basically not a full effort and isn't worthy of keeping it around.