I think the most thankless task was the letterer--at least back in the day when there were people who really did letter comics by hand. I read an article, many years ago now, by one fellow who had been a letterer at DC and he never got any rest. He had to be lettering all the time just to make ends meet and the publisher made all kinds of demands on him, without any compensation for the extra hours he had to put in, the page rates being so low. And you can imagine how much strain it puts on your hands to be doing all that hand-lettering, every day, for hours and hours.

And then, of course, with the advent of computer lettering programs many of those guys were put out of work with nowhere to go.