I have seen this cartoon before, but it always gets a laugh out of me:
I don’t have an attribution for source, send one and I will be happy to add it*. Click on the thumbnail at left to see the whole cartoon.
* A google search indicates it might the be work of monkeynoodle.org. Or it could be just another site showing the cartoon. In either case it is in a handy pdf format over on monkeynoodle.