Anna Salamon and I are confused. Both of us notice ourselves rationalizing on pretty much a daily basis and have to apply techniques like the Litany of Tarski pretty regularly. But in several of our test sessions for teaching rationality, a handful of people report never rationalizing and seem to have little clue what Tarski is for. They don't relate to any examples we give, whether fictitious or actual personal examples from our lives. Some of these people show signs of being rather high-level rationalists overall, although some don't.
And, just to check, did you make sure that all the diet-related examples you got were examples of making false excuses to oneself, and not just examples of e.g. previously intending to diet, but then changing one's mind when one saw the chocolate cake?
yep, they were all valid examples of rationalisation