After years of working as a sole developer with one git master branch, I am investigating using additional branches.  My plan is to keep master as a production-ready branch, do development in a develop branch, and create feature branches off develop.
After much reading, I have created a branch (from my master branch), called develop:
git checkout -b develop
I then created a feature branch off develop:
git checkout -b my-feature
I then modified a file in the my-feature branch and switched back to develop as follows:
git checkout develop
The problem is that when I view the file I changed in the feature branch, the change is still visible. Why is that so? I am on the develop branch!
 
     
    