Front-end web work, at its basic level, is not hard in the traditional "let's go shopping!" sense, but what I find maddening is how unintuitive some of it is (CSS, I'm looking at you). Then you have to worry about how broken or incompatible browsers are. I think "pain in the ass" is a more apt term.

When you get deeper into the UX, things like A/B, optimizing load time, scaling the backend, etc, and that is where it becomes less tedious and the domain knowledge required is more respectable.