When expanding region you can unexpectedly end up with rectangle selection

[glucas]

For example, in the middle of the word 'interactive' below and start hitting C-SPC repeatedly. Selection expands to the defun, then switches to rectangle selection.

(defun smart-region-off ()
  "Reset C-SPC to original command."
  (interactive)
  (define-key global-map [remap set-mark-command] nil))

You can always hit C-SPC twice to start expand-region and then switch to SPC, but it might make sense to handle this case and continue calling expand-region once you start.

[glucas]

If we fix #3 then this problem won't really come up anymore. The typical expand-region pattern would then be C-SPC SPC (SPC)*.