Great Expectations

My Mother in Law is a very negative, conservative woman who holds unbelievably unreasonable expectations for her only child. Nothing ever seems like enough and she always thinks the worst. Why does she doubt her "son" so much? Why does she have this certain attitude towards this one person? Is it that she has pent up frustration from her obvious disdain of our untold lifestyle? Is it worse in her mind than the truth?
Poor Beth, no wonder she is nervous about her parent's reactions. When they treat her this way without the truth, I'm concerned about how terrible they will be to her with it.