I say this to people frequently: don't confuse the way things are vs the way you wish things were. It seems to be the source of so much poor decision-making and misery.
There's the is-ought fallacy.
There's also wishful thinking: believing that what you want / would prefer is what should be, or that a realistic but unpleasant appraisal is wrong or false because it is painful to consider. (Truth and reality don't much care about your preferences.)
Or are you referring to something else?