rational
Explanation
The Joke
A woman is breaking up with a man, telling him: "I'm breaking up with you because you're too coldly rational." The man responds: "From a physics perspective, you breaking up with me is the same as me breaking up with you." She gives him a look and says, "Fine! Got it! Bye!" In the final panel, the man is alone, and the caption reads: "From a physics perspective, the tears are crying me."
The comic plays on the stereotype of the hyper-rational physicist boyfriend who can't stop applying physics frameworks to emotional situations. His first response to being dumped is to invoke Newton's Third Law (or the symmetry of reference frames in relativity) -- if she is moving away from him, from his reference frame, he is moving away from her, so really "who's breaking up with whom?" This infuriating response perfectly validates her reason for breaking up with him. But the final panel reveals the crack in his rationalist armor: he's clearly devastated, and his attempt to maintain the physics framing while crying -- "the tears are crying me" -- shows how absurdly his coping mechanism has broken down.
The Humor
The humor builds across the strip in a classic three-beat structure. The first beat establishes the conflict (too coldly rational). The second beat demonstrates the problem perfectly (applying physics symmetry to a breakup). The final beat subverts the setup by showing that his rationalism is just a defense mechanism -- he is clearly heartbroken, but he can only express that emotion by filtering it through the same physics framework, producing the absurd and poignant phrase "the tears are crying me." It is both funny and oddly sad, which is a hallmark of Weinersmith's best character-driven strips. The joke also works as a commentary on how "rational" people often use intellectual frameworks to avoid confronting their own emotions.