White picket fence

a state of mind where a person blindly holds on to the idea of their perfect lifestyle, regardless of the inevitable life factors that make it impossible for it to be true.

For example if your mom keeps acting as if your family is that all American "white picket fence" family from the 50s, when no one acts or thinks that way (Extreme example:your parents expected everyone to come home and talk about their day but your brother is hooked on meth and never comes home while your sister is at her boyfriends house pretending she doesn't have a family).