Zach has a one track mind
At the end of It’s a Terrible Life Sam, dissatisfied with the life that has been given to him, has an office meltdown and quits. Much like leaving the life John foisted on him, Sam is able to make a stand and walk away. This is very different from the way Sam deals with season 4 Ruby. At the end of season 3, Katie Cassidy's Ruby had a "my way or the highway" mentality and that didn't work with Sam. But this season, Ruby's been in and out of Sam's life - offering suggestions, offering CHOICES. She flat out says it in Lucifer Rising that she just laid out the choices and Sam picked the "right" ones (for her adgenda) every time.
At the same time, at the end of Terrible Life, we see Dean at his desk, back to the grind. He may have some doubts about his path, but at the moment he is staying the course.
Zachariah comes in and starts pushing his buttons - offers a raise and in “eight to ten short years” the chance to be Senior VP Great Lakes Division. Dean realizes and then verbalizes that he has “some other work I have to do” - nice use of repeated language harking way back to “we have work to do” from the pilot.
Once Zach wakes Dean up and they start to talk, Zach never once mentions or even references Sam. Dean yells about Zach getting kicks about “watching us run around like ass-clowns in monkey suits”, so from Dean’s perspective Sam’s part of the package - there's always an "us" as far as Dean is concerned. But Zach focuses completely on Dean - his work, his destiny, his call to be a hunter.
What I find fascinating about this is that if Sam hadn’t been part of the scenario - having weird dreams, dealing with his friend’s death down Tech Support - Dean wouldn’t have been pushed to change. What gets the ball rolling for Dean is working as a TEAM with Sam - a fact that Zach seems happy to ignore.
We see this again in Lucifer Rising - Dean is desperately trying to reconnect with Sam, while Zach disregards Sam other than acknowledging that he has his part to play. I love that by the end, Dean could care less about heaven and hell. For him it all comes down to people and family, and all the pain that goes with it.