I'm not long out of an eating disorder, so telling myself, "No, you can't have..." is a fairly destructive behavior for me. So I do it in reverse. I don't restrict myself from having anything, at all, and I refuse to feel guilty if I have it. When I don't place limits on my stressed out mind, and really, genuinely, allow myself anything I want, my better judgement usually wins and I don't get whatever it is that I thought would make me feel better. It's a little trick my psych major taught me (before becoming useless). The more you fight yourself, the more you spend mental resources that are already limited by stress. Next time you're holding a dress thinking, "I really shouldn't" just tell yourself "Actually, it's perfectly fine. Go ahead and get it." (and mean it!) I'd be willing to bet the price of that dress that you put it down and walk away with no regrets.