Actually that 80 hour a week guy will quit without notice really fucking the company.
Hell I took my vacation time left and called in sick for the last days I had in my sick bank while I worked at my new job.. the day I was supposed to be back at my old job I walked in at 8 am dropped my badge and keys on my bosses desk and said, "I quit, hope you can hire the 3 guys you will need to replace me quickly." I had informed HR that I was quitting in writing that morning at 7am when they got there.
It screwed them over hard, really hard. I got a call from the VP begging for me to come back with a 30% pay increase 2 hours after I walked out the door. I said he doesn't have enough money in the world for me to work there anymore, I wished them luck replacing me.
Funny thing, 6 months later the 2008 crash happened and they closed up for good.