My coworker said he was quitting because he felt like a forgotten semicolon.

This joke plays on a clever analogy and a dose of dark humor. The setup uses wordplay by comparing a feeling of being overlooked at work to a "forgotten semicolon." In writing and many programming languages, semicolons serve a crucial, yet often subtle, role. They can be easily missed or misused, and sometimes their absence isn't immediately noticed, making them a perfect metaphor for someone feeling insignificant or expendable in an office environment.

The humor then pivots to irony with the punchline. Instead of offering reassurance, the response bluntly confirms the coworker's fear of being unmissed. This resonates with the common, albeit cynical, sentiment that some individuals in a large organization might indeed be easily replaced or forgotten. It taps into the shared experience of workplace dynamics where people can sometimes feel like just another cog in the machine, making the joke both relatable and a little bit cutting.