How do towels stay on hooks?

Towels (and coats) are often stored on hooks, like this: To the untrained eye, it looks like the towel will slide off from its own weight. The hook usually angles upwards slightly, but a towel does not have any "handle" to string around and hang on to the hook -- this makes it seem like it will simply slide off. Yet these hooks hold towels well, even heavy bath towels. Why? I have three ideas: There is sufficient friction between the towel and the hook to counteract the force of the towel pulling down. The hook is angled such that the force is directed into the hook, not directed to slide the towel off of it. The center of mass of the towel ends up below the hook, since the towel is hanging against the wall. Which of these ideas are likely correct? I am also happy with an answer based purely on theoretical analysis of the forces involved.