My mother's PB is incredibly short (hardly any advice or counsel at all), and this was from a man who was known for his long blessings. My mom is too humble to admit it, but, looking back at her life, she really didn't need much counsel or advice. However, the two things that were said were absolutely spot-on and described a mental condition that was undiagnosed until almost 10 years after the blessing and unknown at the time by her family.
Looking back on my wife's life thus far, her PB identifies every single one of her major issues - those with which she struggles continually. It's not self-fulfilling prophecy, but rather real insight into many issues of her upbringing and natural tendencies. One fascinating aspect of both of our blessings is that the focus in each section dealing with marriage is her. (She is the focus in hers, and she is the focus in mine.)I believe the concept of Patriarchal Blessings is powerful and inspired, but I believe that they are only as infallible as the individual who gives them - meaning that none of them are completely infallible. I also believe that very few of them are inevitable. My mother's experience is an exception that proves the rule, I believe, since she herself is an exception that proves the rule. The process and the event are an amazing part of my own testimony of the Restoration, but what I make of my Patriarchal Blessing still depends on me.