Coming from CVS and ClearCase it took me some time to adopt to Git. The fact that it was distributed was confusing at first, for example, because I thought that would cause chaos. But the way we used it was actually not “that distributed”. But once I understood how it worked, not doing DVCS was “the wrong way” immediately.
The staging area changed the way I work for the better. When I develop something, a file can be at the same time “not modified yet,” in progress where I can carefully accept or reject the modifications, and partially done when the parts have been confirmed and added to the staging area.
Once nothing is “in progress” anymore, I know that my future commit is almost perfect and I can quickly review my stuff before committing. It’s faster and more safe than other tools.