I recently discovered a way to learn Vim without fear: learn undo ('u') first! If you know that, you can just mess around with Vim commands until you inevitably screw something up, undo the changes, relax, take a deep breath, and Google whatever you're trying to do.
... and this to go back to the state of the file 10 minutes ago:
:earlier 10m
and
:later 10m
to go back. Note: This is independent of undo/redo cycles as Vim keeps track of that in a tree-like structure. There's just no really great default way of accessing it. See Gundo for a plugin that tries to make it more accessible.
