Even if you're on your own branch you can easily get a DAG after rebasing or resetting. The reflog keeps track of the history of all refs (ie. branch names) tha

Even if you're on your own branch you can easily get a DAG after rebasing or resetting. The reflog keeps track of the history of all refs (ie. branch names) that you change. After you rebase your old commits are still there! It's actually quite hard to remove commits. Trusting the reflog is key to becoming good at git.