Shazzbaa makes a great point about Hyperbole and a Half: That it doesn't look like Rembrandt doesn't mean it's bad. The illustrations are clear in intention and emotion, we understand at once what's going on, and the slightly unsettling style supports the slightly unsettling content. It's all clearly intentional, and it works.
I also think everyone has different criteria for "good art" in comics. Some don't mind stiffness if the faces are pretty, others want motion and action more than pretty faces, for example. Same goes for what "repels" people: I don't mind if the legs are a bit too long in one panel, or even if the artist goofed up and put the thumb on the wrong side in a tricky pose, but murky shadows made with a black airbrush/soft edge brush is something that turns me off instantly. (Use color in your shadows, people! And some shadows have hard edges! Ahem. Back on topic.) Meanwhile, someone else might like the "gritty" look of black airbrush shadows, but thinks that spot-on anatomy is everything. Meanwhile a third person is annoyed by wonky perspective, while they don't mind scribbly lines. It's so subjective.
So basically, do your best, you'll improve, and at every point in your comic-making career, there will people who like it, and people who dislike it. (Also artists are rarely satisfied with their own art it seems, so don't beat yourself up over that either haha)
As others have pointed out though, the most universal criteria seems to be clarity. What's the point of drawing images if nobody can tell what's going on? Make that your primary focus!
