git branch before pull

Things are going well on your version of production/master and you'd like to pull the latest iteration. Oh, sure, you could tar your setup before doing that in case it breaks, but maybe you're stuck for time and too lazy. That's okay. Really it is. just
git branch before-pull-todaysdate
git pull

PANIC! bad stuff, things crashing, etc... maybe that pull isn't nice.
git checkout before-pull-todaysdate

whew... sanity restored. ... OK, it's off hours and you really want to get back to the latest iteration. Managers aren't on your back and you can fix this.
git checkout master

errors, etc. but at least you're at the latest iteration.

BETTER: don't pull. Just git fetch, then git merge when you're ready.

git branch change oops wrong branch

Specific case:

You're working on a feature but forgot to change branches. This feature is going to corrupt master, it seems, but you haven't committed yet.

alternative to stash,
git branch newbranchname
git checkout newbranchname
git add .
git commit -m "I needed a branch for this before killing master"

if you git checkout master, all these new previously uncommitted changes aren't there (whew) but git checkout newbranchname has the stuff you've been working on.

when you're ready to put them back, just merge back to master.