Thank you and thanks for taking the time to comment.
I think it is because we aren't really programmed to look at things numerically but they trigger emotional reward/pain centers so we have a hard time teasing them apart. I am guessing even someone like you who spends a great deal of time in the numbers doesn't see all of the little implications of each or the effects they might have on your thinking or feelings.
Like the cream cake, one tastes good, maybe even two but we don't know how the future feeling will be until we are actually overweight and experience it.