Carefully Monitor Your Dosage
Laughter can be the best medicine, but—like drinking too much cough syrup—it can also be poison. Roger Rabbit shows us both the benefits and the dangers of laughing your butt off. Not literally. (Hey, this movie is half cartoon—anything is possible, even exploding butts.)
Eddie and Roger are on two opposite sides of the humor spectrum. Eddie's humorless; Roger will stop at nothing to get a laugh. This is a big point of contention for the two, and often puts them at odds, which we see play out in this little argument
VALIANT: You crazy rabbit! I'm out there risking my neck for you and what are you doing? Singing and dancing!
ROGER: But I'm a Toon. Toons are supposed to make people laugh.
They grow together over the course of the film, though. Roger learns to take things a little more seriously, and Eddie develops a sense of humor. In fact, it's Eddie's slapstick routine that turns the tables in Eddie's favor at the end of the movie. Doom always warned the weasels they'd laugh themselves to death…and they do.
Roger cheers Eddie on like this:
ROGER: Hey Eddie! Keep it up! You're killing them! You're slaying them! You're knocking them dead!
These are all showbiz phrases for doing a great job at entertaining an audience. But here, they prove 100% true, as Eddie makes the weasels literally laugh themselves to death. Or as dead as Toons get when they turn into little ghost versions of themselves.
The Good Humor Man
Eddie's zany triumph harkens back to two comments earlier in the movie:
DOLORES: Is he always this funny, or only on days he's wanted for murder?
ROGER: Listen. My philosophy is this. If you don't have a good sense of humor, you're better off dead.
And in the bar, Roger says that a snitch wouldn't turn on him after Roger makes him laugh.
ROGER: A laugh can be a very powerful thing. Why, sometimes in life it's the only weapon we have.
The humorless Eddie from the beginning would have failed against Judge Doom and the weasels. It's laughter that acts as a weapon and saves the day. Who needs swords and guns when you have jokes and puns?