What I noticed when I checked out at work is that it also makes me check out in my personal life (PL). It bleeds in. Generally, in my personal life I'm not checked out. That bleeds into work.
So work bleeds into PL and PL into work. I found that it was painful for work to bleed into my PL like that since I'm switched on and I just had this hint of "ah... whatever who gives a fuck."
I give a fuck.
I give a fuck because it's my life. I do it for myself. I don't do it for my boss or my colleagues. I do it for me.
I've found that this attitude is way more helpful to me as two things happen:
1. I'm more productive at work so I don't have to cover my ass at all. When I was in the "Who The Fuck Cares" club, I needed to cover my ass once per month (read: I didn't do anything for like 3 days and people were expecting results on day 4).
2. Since it's in service for my personal life, I don't go too far. The moment I notice that work encroaches too much upon personal life, my instinct comes back immediately and I pay my visit to the "Who The Fuck Cares" club, and party as long as I want to.
That's the balance I'm currently taking.