Autocomplete rocks. Undoubtedly.
… but since I know what to type, and since I can type faster than any autocomplete known to me, here’s how to disable it, in Emacs:
(if (fboundp 'global-auto-complete-mode) (funcall 'global-auto-complete-mode -1))
The if is important should you wish to use the same initialisation file with an emacs that does not know autocomplete, e.g. those of older Smallworld™ installs.