He might not be bright yellow and bald, but The Day of the Locust's Homer Simpson shares a few personality traits with his famous namesake. He's pretty chill. He's not the sharpest crayon in the box (though he never did stuff one up his nose). And, in general, he's a friendly guy.
But that's about where the similarities end. While Homer Simpson of Springfield enjoys a laugh-a-minute life of cartoon hijinks, our Homer is stuck inside the dark, seedy underbelly of Depression-era Hollywood. As it happens, that's not exactly a fun place to be.
Here's one thing that sets our Homer Simpson apart—he's definitely an innocent guy. Homer has spent his entire life working as a hotel manager, but "the forty years of his life had been entirely without variety or excitement" (10.1). Unlike "the people who come to California to die," however, Homer hasn't fallen victim to the materialistic American Dream. That's an important distinction. While those folks become bitter when they reach the boring years of retirement, Homer finds California boredom to be the most exciting thing in the world.
Despite this simple-minded contentment, Homer is haunted by what happened with Romola Martin. Actually, it might be more accurate to say that he's haunted by what didn't happen. He had been working at the hotel one day when she made a drunken advance toward him, which he promptly rejected and then "labeled his excitement disgust" (8.20). He even steps back up to bat a second time and strikes out once again, which is a failure of nerve that haunts him to the present day.
As you can see, Homer has a definite inability to go with the flow. For example, he has difficulty comprehending his own emotions, and he frequently becomes overwhelmed when they come on too strong. This dynamic can be seen in his strange disconnection from his hands: "his hands seemed to have a life and a will of their own" (10.2). Homer's independent hands are a reflection of his detachment from his emotions and inability to understand his own actions as a result of that detachment, especially when he feels compelled to do strange things—like get down and dirty with Romola Martin.
You can't keep things bottled up forever, though. After turning to Faye in a misguided attempt to exorcise Romola Martin from his memory, Homer is left with nothing but disappointment when she dumps him. This really messes him up and amplifies his weirdness—"Homer walked more than ever like a badly made automaton and his features were set in a rigid, mechanical grin" (27.23). If you thought that the guy was disconnected from his emotions before, then just wait until you see this.
In the end, Homer accidentally sparks the novel-closing riot by releasing his frustrations on a small child. That wasn't the best thing to do, sure (not that we're big fans of Adore Loomis), but we think everyone is using him as a scapegoat. As we've mentioned elsewhere, "the people who come to California to die" are desperate to release their feelings of disappointment in any way possible, and no one's an easier target than the middle-aged weirdo wandering around in a bathrobe beating up kids.
Harsh. Still, it's the logical culmination of The Day of the Locust's critique of modern American society—in a world this messed up, the most innocent among us are the most easily victimized.