Were you speaking of Frederick William I? While your previous comment made me shrug, this one made me laugh. One single person's character can never define a nation, not even his/her own family. Aggressive persons can be found anywhere and in any period of time, but we never blame there descendants for having such ancestors. Do not be deceived by stereotypes.
It is just one memoir that I named as an example. The Prussian RF certainly was not a happy family and the individuals of that family didn't count much, were they daughters, sons or wifes. And that shows in their memoirs - and the reasons for that.
As for the political individual - just look at the history of the rise of Prussia to become the leading nation of Germany at all costs: successful but ruthless. Ponder the reasoning why the king of Prussia did not become German emperor in 1948 - he did not want a crown offered by the people's representatives...
And I don't blame Georg Friedrich for his ancestors. I just don't want a Prussian Hohenzollern as Head of my State.