relatable
Explanation
This comic shows the red-bearded SMBC author-avatar character (representing Zach Weinersmith) delivering what he apparently considers a relatable observation: "Cats are smaller than dogs on average and so produce less urine, making them less useful as a source of nitrogen. In this regard they are different."
The caption reads: "Every time I try to make relatable humor I reveal myself as barely human."
The joke operates on a meta-comedic level. The character is attempting to participate in the popular genre of "relatable humor" -- the kind of observational comedy that earns knowing nods from audiences by pointing out shared everyday experiences (like losing your keys, or the awkwardness of elevator rides). Instead, his attempt at a relatable observation about cats versus dogs veers immediately into the comparative nitrogen output of animal urine, which is the kind of thing only a deeply science-obsessed person would find relatable.
The humor lies in the gap between intention and execution. The character genuinely seems to think that comparing the agricultural utility of cat versus dog urine is the kind of thing normal people think about. The caption's admission -- "I reveal myself as barely human" -- is the punchline, acknowledging that the very act of trying to connect with ordinary people only further exposes how far his thought patterns have drifted from normal human concerns. It's a self-deprecating joke about being a nerd so deeply embedded in scientific thinking that even casual conversation becomes an exercise in quantitative analysis. The phrase "in this regard they are different" is a particularly nice touch, delivered with the flat precision of a scientific paper's conclusion.