Fixing a messed up git directory

Following situation:
You have got a cloned repository in your home directory, you noticed that something changed upstream und you want to get all the fancy changes. You do a:

to get the latest tag. What you didn’t check: What is your current branch, have you uncommited changes? And boom, everything is broken:

How do we fix that?
We start with:

What does it do?

Resets the index and working tree. Any changes to tracked files in the working tree since
are discarded.

Than we add:

This basically deletes all untracked directories and files. We can simulate this with:

Now we got a clean directory again, all files with merge conflicts or whatsoever are gone. Please note that this will also remove every change that you did before the pull but forgot to commit. If you want to keep that changes than you shouldn’t copy&paste the git commands!