Even though it's a bit of a cheapshot to nominate a Golden Age cover for W.C.E. (considering the much lower production standards of that era), the cover of Green Lantern #22 (1946) was clearly asking for it.
Here we see a sentient tree giving Green Lantern's sidekick Doiby Dickles the walloping of his life, while G.L. smirks in the background. Granted, his magic ring was powerless against wood, so there wasn't much Green Lantern could do to help Doiby...but you'd think he could at least muster a little concern for his helpless pal. Maybe his massive, mutated left arm is making him a little giddy.
I think what bothers me the most about the cover isn't so much the scene itself, but rather the larger Golden Age trend of DC attaching dopey comic relief characters to otherwise cool, immensely powerful characters.
In addition to Green Lantern's Doiby Dickles, the original Flash (Jay Garrick) was stuck with The Three Dimwits (a.k.a. "The Three Idiots" or "The Three Numbskulls"). Imagine....the Fastest Man Alive, forced to play straight man to Winky, Blinky, and Noddy for dozens of adventures.
Worse by far was supernatural powerhouse The Spectre, formerly the vengeful agent of The Voice (God), reduced to playing "guardian angel" to Percival Popp, the Super Cop.
So, yeah....seeing Doiby Dickle's fat backside getting paddled by a jolly tree is bad enough...but added to the larger trend of handicapping otherwise cool characters with clownish sidekicks, it's easily one of the Worst Covers Ever.