My elementary school teachers used a similar metaphor with alligators. But I never could remember which number it was that got eaten, so I just figured the bigger side was for the bigger number. Since an equal sign doesn’t have a “bigger side”, it would imply that both sides are the same. Then I wondered why they didn’t just teach that. Then I liked school even less.

(Oddly enough, my childhood intuition about equals signs isn’t historically accurate—the equality is actually supposed to be represented by the equal length of the two strokes.)