What Are Your Favorite Cartoons?

This post originally appeared on the Software Carpentry website.

As we're updating our lessons this year, I'd like to add a few more cartoons that relate directly to what we teach. Two of my favorites are [this description of how most scientists manage revisions](http://www.phdcomics.com/comics/archive.php?comicid=1531) and [this summary of how many people react to unwelcome evidence](http://www.felienne.com/archives/4404). What are yours, and what lessons would you add them to? Please add links in the comments on this page (and please make sure what you link to has enough information for us to contact artists and make sure we have permission to re-use their work).