Here's the incident (and litmus test from my cofounder) that permanently changed my workaholic thinking:
cofounder: Hey Ed, it's 6:30. Finish up. Let's go next door and get a beer.
edw519: No, I have to finish <Task X>.
cofounder: Do that later. Have a beer with me.
edw519: No, I have to finish this now.
cofounder: Have a beer with me, then do that tomorrow.
edw519: No, this has to be finished tonight.
cofounder: Then have a beer with me, and come back after the beer and finish it tonight.
edw519: No, I have to finish it first.
cofounder: If you have a beer with me and don't finish that, how will our Annual Report be different?
edw519: What?
cofounder: You heard me. If you have a beer with me and don't finish that tonight, how will our Annual Report be different?
edw519: I don't understand.
cofounder: Listen one more time and answer the fucking question! If you have a beer with me and don't finish that tonight, how will our Annual Report be different?
edw519: It won't be.
cofounder: Good. Then let's have that beer now. OK?
edw519: OK.
cofounder: Hey Ed, it's 6:30. Finish up. Let's go next door and get a beer.
edw519: No, I have to finish <Task X>.
cofounder: Do that later. Have a beer with me.
edw519: No, I have to finish this now.
cofounder: Have a beer with me, then do that tomorrow.
edw519: No, this has to be finished tonight.
cofounder: Then have a beer with me, and come back after the beer and finish it tonight.
edw519: No, I have to finish it first.
cofounder: If you have a beer with me and don't finish that, how will our Annual Report be different?
edw519: What?
cofounder: You heard me. If you have a beer with me and don't finish that tonight, how will our Annual Report be different?
edw519: I don't understand.
cofounder: Listen one more time and answer the fucking question! If you have a beer with me and don't finish that tonight, how will our Annual Report be different?
edw519: It won't be.
cofounder: Good. Then let's have that beer now. OK?
edw519: OK.