If you have a file like ``` jjjjjj | ``` and you have `imap jj <Esc>`, autocompleting the `jjjjj` will cause you to leave insert mode, and not have the `jjjjj` inserted.
If you have a file like
and you have
imap jj <Esc>, autocompleting thejjjjjwill cause you to leave insert mode, and not have thejjjjjinserted.