The Guy Who Asks You To Work On Sunday

I never wanted to be 'that guy.' At first I hated 'that guy,' then I began to understand 'that guy' didn't do it out of spite, 'that guy' didn't want to do it, either... and then I became 'that guy.'
'That Guy' is the person that asks you to work on a Sunday.
I've been working almost every day since I returned on a project that I have no love for and that I would walk away from in a heartbeat. Some people thrive in the intense atmosphere, some people really turn out spectacular work under pressure. I don't know any, but I've heard they exist.
This project has burned through 2/3 of my company, subject one guy to work so hard he hasn't recovered from his flu for over a month. The site is an hour from where I live, and then I get to work 10-12 hours, drive home, sleep, and do it again. The client is using the opportunity to treat us like crap during the entire time. And why not? It's what we get paid for, to take the crap they don't want to or can't give to their own employees.
I'm not even the project manager. But I'm 'in charge' today. So that means I get to make sure people are coming to work on a Sunday. When I interviewed with these people, I said I would work 16 hours a day during the week, but would not work weekends. I'm now working 12 hour days and weekends. Hell, even union employees get two days off every two weeks.
I've worked weekends before, and I've not had a problem with it. This issue isn't about working weekends for me, but the prolonged requirement that I will be needed to work weekends. At least two past this one, possibly more. There's a semi-defined goal, but it shifts hourly during the week. I don't even know if what I'm working on is still legit anymore.
So put yourself in my shoes. You don't want to be there but you know the only way for you to achieve your goal is to be there with as many people as you can muster. Then you get a call. One of the guys scheduled to work Sunday is not coming in. Last minute notice. You make a request that the guy send you the file he's working on in an email. He says no, he won't fill your request, he doesn't understand why he needs to do that. The other guys on the team don't get along and only one is helpful to you.
I let his boss know, and I let his project manager know. It's all I can do.
I know that managment is about getting people to do work. What they don't tell you is that it's more to get them to do work they don't want to do. Motivation. It's hard to motivate people when you are not motivated yourself.
So the next time you are asked to work a weekend, or outside of your normal scope of work, remember the person that asks is only a jerk if they're not in there slogging it out with you.