A Facebook friend recently posted that she, "Might be a bit shopped out," after having spent a day or two in intensive shopping. Here is what she really meant, in econ-speak:
At the time that I posted that status update, the expected additional or incremental benefits from additional shopping were out-weighed by the expected additional or incremental costs of additional shopping, and so I decided to stop shopping even though I fully understand that if I had continued to shop I would likely have acquired additional information and that by stopping now I might miss out on some good buys.
Note the importance of the word "expected". She didn't know for sure, but she had formed an estimate of the relevant probabilities in her own mind. Based on those expectations, she decided to quit.
And even though the rational expectations cowboys of the economics profession don't like to admit it often, she undoubtedly formed her expectations based on her past experiences and acquired information; i.e., most rational shoppers have adaptive expectations.