Several years ago when I was using Weight Watchers to help me drop some extra pounds I allowed myself one day each week to some of my favorite foods. Typically this involved a trip to the local movie house and a medium size bag of popcorn with "extra" butter.
I'm back on the WW program again and once again I do allow myself some "cheating". I went home last week to spend a few days with my parents and siblings and the eatothon started the moment I walked in the door and ended when I backed my car out of their driveway. My mom fixed all my favorite foods and I just couldn't say no. Thank goodness I had taken a bike with me and could buzz about town each there I was there or the weight gain would have been more than the increase of 1.5 pounds the scales showed when I returned home.
I think you have allow yourself those cheat days. In moderation they are good for your morale and keep you working towards your goals. They only become bad when they start to occur every day and your caloric intake far exceeds the calories being burned off each day.