Manager
Explanation
This comic plays on the "I want to speak to your manager" trope -- the stereotypical demand from an unhappy customer. A man with glasses demands to speak to the manager, and the red-haired character (a stand-in for cartoonist Zach Weinersmith) proudly declares: "I'm a self-employed artist! I am my own manager!"
The man then simply says: "Your comics are bad." The final panel shows the artist deflated, with no comeback -- because there's no higher authority to defer the complaint to.
The humor works on multiple levels. The typical "speak to the manager" interaction assumes a corporate hierarchy where the employee can pass the complaint upward. A self-employed person has no such escape route -- they have to absorb the criticism directly. It's also a self-deprecating joke from Weinersmith about being a webcomic artist, where there's no buffer between creator and audience. The artist's initial pride in being his own boss instantly becomes a liability when it means he's also his own complaint department.