This is from a FB article in which 10 dog breeds are listed as being "difficult." Most of the others were hounds, which can be very independent and energetic.
Beautiful and fluffy, the Kuvasz breed has a mind of its own. They’re suspicious, guarded, intelligent and bred to work. If you want a Kuvasz, you need to be willing to put in a lot of time exercising your pup. You also need to be prepared for constant furbombs all over your house. Invest in good vacuum.
They are gentle and loving to their humans, “their” being the operative word. The breed’s reclusive nature can make them overly suspicious of strangers. This makes early socialization a must. It also means there’s a whole lotta barkin’ going on. A Kuvasz’ size can make them difficult to control, as well. They can clock in at 115 pounds! A consistent owner is a prerequisite here.