Reptile Brain
Explanation
This comic plays on the common pop-psychology concept of the "reptile brain" -- the idea that humans have a primitive, lizard-like part of the brain responsible for base instincts and emotional reactions. A man named Dave apologizes for yelling at someone, attributing his outburst to his "reptile brain."
His companion points out that there is actually no good excuse for yelling, and that the "reptile brain" concept (referring to the triune brain model proposed by Paul MacLean) has been largely debunked by modern neuroscience. The deep brain structures sometimes called "reptilian" are not actually the seat of aggression in the simplistic way pop psychology suggests, and they don't neatly map onto emotional behavior.
In the final panel, a literal reptile brain (drawn as a small reptile face on the man's brain) is shown to be "angry at you but still loves you," which is both the punchline and the emotional resolution. The joke works on multiple levels: it mocks the way people use pseudo-scientific language to excuse bad behavior, while the final image undercuts the debunking with a cute, literal interpretation that is emotionally satisfying even if scientifically nonsensical.