Git continues to be a real impediment to new users on Pantheon, just like when I worked at a dev shop. We try to make it pretty easy at Pantheon, but if one veers off course of a standard Dev/Test/Live workflow, or God forbid, they make a mistake, its easy to get sucked into the vortex. We are working to make explaining it a bit easier. I have recently been introduced to a few new sites I think are helpful in explaining more complex workflows:
Visualizing Git Concepts with D3: This has some pretty good simplified tutorials using javascript to show what is really happening with various commands.
Atlassian Git Tutorial: Atlassian really took the time to do it right. These are written much better than other git docs I have seen.