"Mental Metamorphosis" - a term coined to explain the ever changing mentality of a human being. The take-away from this is that not only are your thoughts unique compared to others, they're also unique within yourself based on the time frame. I'm not going to dwelve into time being the 4th dimension of space etcetera, but time has an essential quality to itself.
What do you think is the closest relationship that is innate and what is the best relationship that is acquired? My opinion that I just give as an example - The former is that between a mother-child and the later is that between you-significant other. You might have a different opinion, but whatever it be, these are the relationships where the two people involved seem to have a perfect understanding of the mentality of the other. Is this possible, especially when the mentalities of both the people are changing with time. Do you understand yourself completely in the first place, and when you do understand yourself, hasn't the time moved and you're already outdated in your understanding?
Think of this as Heisenberg's uncertainty principle which states that "The more precisely the position is determined, the less precisely the momentum is known in this instant, and vice versa". Translated in a crude manner, the statement says that one cannot measure both the position and momentum of a particle accurately. In our context, one cannot know the mentality of a person and the precise time of that mentality accurately.
When you hear well-known philosophers say that they're in search of who they are, I wonder if they're trying to race against time. It's not possible. Mentalities change, they metamorphize to something that you yourself can't predict, let alone someone else. Trying to understand anything "completely with precision" is trying to race against time, a concept that I cannot absorb.