grind
Explanation
This comic satirizes the concept of "the grind" as it applies to both academic and athletic pursuits.
In the first panel, a child asks her mother how she got good at her profession. The mother, a teacher, says "the key is the joy of discovery." In the next panel she elaborates that this joy comes through "endless, horrible, hateful grinding." The child confirms: "That's right."
The third panel describes the process in dramatic terms: after several months of "crying, screaming, and banging your head on your books," you eventually gain a glimpse into "the master beauty of the universe" -- and that glimpse is just enough to make you go back for more.
In the fourth panel, a second character observes that this sounds a lot like sports: you endure a "mountain of glass and hot coals" of training and suffering, and then you get a single, brief "glorious moment" that keeps you coming back.
The joke in the final panel ties it together: one character says "please, just say you enjoy your work," while the other wonders why sports are considered "healthy, effective practice" but the same grueling approach to intellectual work is considered "bad and wrong."
The humor lies in the observation that society romanticizes the suffering involved in athletic training ("the grind") while viewing the same kind of obsessive, painful dedication to intellectual pursuits as unhealthy or abnormal. Zach Weinersmith is pointing out this double standard: both paths to mastery involve miserable persistence punctuated by brief transcendent moments, but only one is culturally celebrated.