If you do a filter like this: All mail that arrives to john.s.m.i.t.h@gmail.com is important. Everything else is spam. Of course you might not get emails from p

If you do a filter like this: All mail that arrives to john.s.m.i.t.h@gmail.com is important. Everything else is spam. Of course you might not get emails from people who sends emails to john.smith@gmail.com nor johnsmith@gmail.com because the emails go to spam.