Ditto!
I'm not sure it's "working harder," so much as working without a break from responsibility. An office worker, or even a factory worker, gets a break. He can go to the bathroom on his own. He gets a lunch break. He can take his eye off his coworkers, and not have them all disappear outside into a mud puddle. He can take sick leave if he's sick, and go to the doctor *by himself*. If he has to go on a business trip, or just to the gas station, he's only responsible for himself.
My husband once said, "Well, I'm responsible for the guys who work for me!" and I said, "You have to take them to the bathroom? Do they have clean clothes, if you don't do their laundry? Do they eat meals that you don't fix? What if they wake up in the middle of the night ... do you have to figure out their problems and get them back to bed? Wow, and these guys are earning a salary?!"
This is not to say that I feel oppressed about my life as a homeschooling mother of seven ... I wouldn't do it, if I weren't content. Just pointing out that to me, what makes it "hard" is not teaching phonics, doing laundry, or cooking meals, but rather the *responsibility* that you never get away from.