Actually Dilbert is a bit inaccurate here. It is widely accepted among scientists that the donut is not needed for time to be created by the donuts rotation. However, the necessity of the cannon is still part of a controversial discussion.
This is easily in the top three for me.... it makes me laugh hard every time. I love Dilbert because it consistently points out that there are multiple reasons why ideas can only be implied: when it comes down to it, there are few people who are smart enough to both understand and communicate much of anything.