Sometimes
Explanation
This comic takes the well-known Sesame Street concept of "sometimes foods" and pushes it to a darkly existential conclusion.
In the first panel, a parent tells a child the familiar lesson: "Cookies are a sometimes food" -- the standard nutritional advice popularized by Cookie Monster's reformed eating habits on Sesame Street, meaning cookies should be eaten only occasionally, not all the time.
In the second panel, the child (or another character) responds with an unexpected generalization: "All food is a sometimes food." This is technically true -- you eat any given food only sometimes, not constantly -- but it shifts the meaning from "eat this in moderation" to something more philosophical.
The third panel has someone begin to respond, "Technically true, but--" only to be cut off by the devastating final extension of the logic: "Because all lives are sometimes lives." This takes the "sometimes" framing from a gentle dietary guideline to a bleak existential observation -- all lives are temporary, we are all only "sometimes" alive. Every life is finite, making all existence a "sometimes" state.
The comic's humor comes from the escalation: a simple, child-friendly concept about healthy eating gets logically extended into a meditation on mortality in just three steps. The final panel shows the character staring bleakly, having arrived at existential despair through the impeccable logic of Sesame Street nutritional advice.