The best Envy Shield is to have spontaneous spending as part of your spending plan. If you go too far in trying to scrimp and save, it’s a lot more likely you’ll have a spectacular willpower failure (and the debt that follows) that might have been avoided with slightly looser purse-strings.
Maybe you can’t afford a trip to Disney, but if hearing about your friends’ Disney trip stirs wistful thoughts in your mind, you can raid the Mad Money account for a weekend road trip.
(EDIT: I just realized that “spontaneous” and “spending plan” seems like a contradiction. What I meant was that you should set aside some money in no particular category to spend as you like on fun things. (A nice coat you just saw on sale, a spontaneous weekend away, new gadget, whatever…))