Maintain a single .gitconfig between different operating systems by using proxy scripts for git diff and git merge tools.
You want to share a topic branch with a colleague but do not want to push that branch upstream to Github/BitBucket/GitLab, etc. How do you do this? You could create a patch and email it. Or you could do it in the most crazy way possible and use Apache and allow your colleague to pull from your repo directly. This does take a bit more time to setup, but it would also be absolutely crazy dumb for everyone involved. Basically, let's setup a git server on your workstation!
Here is a rough outline of my Pantheon + Jenkins process. I like my code in BitBucket. I also like Pantheon (check them out). The Pantheon workflow is all about being the source of truth for your code. This is fine, and actually I dig it because it promotes good practices. However, I, and my company, have many projects in BitBucket already, and am using Jenkins more and more for some Continuous Integration functions. We want to keep using BitBucket as our source of truth and our existing workflows, but also want to use Pantheon.
It was brought to my attention at the office that a few of our recently launched websites had publicly exposed .git repository information. Unscrupulous users could use the exposed data to pull down the entire commit history, giving them unfiltered access to what is basically the blueprint for the website.