The major workflow shift that involves the skies parting and mana floating down from heaven when you switch to a DVCS (git, hg) is the ease and lightweight nature of branching.
Having used git for four years, I now feel absolutely filthy if I'm not coding on a branch. If I start coding anything, I make a branch first, because the overhead is nearly zero, if I screw something up I can easily revert, and the downside of being scared to push code is too great.
Example: Yesterday I started a new feature. Step 1 was to branch from our develop branch. A bit into the coding I realized that this feature was going to take longer than expected. I committed what I had on my branch and pushed it to the remote repository (github in this case). This affects no one else, because the code is on a branch.
What really makes this possible is that merging is so easy. Branching and merging in svn was scary. I was never sure if something horrible was about to happen. With git (and hg) branching and merging is the expected behavior, and it's easy.
Always being on a branch also makes it easier to deal with interruptions. "Hey, there's an emergency, can you fix Foo?" No problem, commit what you have on your branch (or use `git stash` which is amazing) and jump back to the branch that has the code you need to fix. Need that fix in your branch as well? You can merge or simply `git cherry-pick` a single commit across branches. You no longer have to worry about the dreaded "Did I already merge this? What if I merge it again, what will happen?"