My astronomy teacher loves analogies. Not a single cosmic event escapes his poetic eye for personification and metaphor. The following is his most recent gem:
"Now, when electron pressure isn't strong enough to retain hydrostatic equilibrium, a star starts collapsing again. Pretty soon, the electrons get squished into the atomic nuclei where they combine with the protons to create neutrons. According to the — which is too complicated to go over here— a free neutron's nature is to split back apart into the proton and electron.
"Perhaps I can illustrate this idea with an analogy. Suppose I were to throw you into the deep end of a swimming pool. Your nature tells you to swim to the top. Now say I were to tie your arms and legs together and throw you back in. [At this point a few students chuckle nervously.] Your nature tells you to swim to the surface, but you can't because of the ropes. The ropes are the Pauli Exclusion Principle.
"It is this pressure from the ropes that creates a neutron star.
I can't wait to hear what he has to say about black holes.
I've also seen people get lost in their own analogies when talking about object oriented programming. I learned from a book that tried to explain classes by likening them to a pizza-creating robot. The analogy failed miserably, and it wasn't until someone told me in my freshman year Java course that, "Classes are just big blocks of data with functions that allow a program to modify the data," that the idea finally clicked. That's why so many non-programmers are terrified when anyone mentions OOP; they have never gotten a good explanation of this relatively simple concept that doesn't bury them in a pile of abstrations and metaphors.