Problem:
We are in the middle of something in development and your customer calls you telling that there is a critical problem in production that must be solved asap.

Solution:

branch:development$ git stash
	>> This will record our changes (not commit) in stash and rever to HEAD
branch:development$ git checkout production
	>> Change to production branch
- Make the changes you need in production
branch:production$ git checkout development
	>> Get back to development again
branch:development$ git merge production
	>> We want the changes made in production applied in development
branch:development$ git stash pop
	>> Reapply our stash (there is also "apply" instead of "pop". Apply don't delete the last stash while pop do)