You must be young. Not that there's a problem with that, as the young usually innovate and put a lot of youthful energy into progress.

As you get older and/or start a family, the thought of 80+ hours a week becomes laughable and even dread-inducing.

If work is hard, I'm probably going to look at a different career. Hard implies suffering and unpleasant obstacles to me. If it's challenging however...