I have owned pit,doberman,rotts,chows,boxers,as well as minni-pins,cats as large as mancoons(look it up).
I have also worked/hallandale k-9 unit force w/ all breeds for domestic,as well as protection trainng.
I have rescued 120 lb rotts from running through a fence after 2 boys,and through a patio glass door. After 24 hrs /the dog..I kept him,adapted him out,hes been great.
My 4yr old 92 pound red nose lets a mancoon cat box /him,alng w/the 3 1/2 yr old grandson.
My point here is;some dogs as like people clash personalities,whether due to blood line, inbreeding, or the owner has no knowledge of the breed and their actual needs.

I'm just saying..