I wouldn't say stubborness is typical of working cockers, I think its down to the personality of the individuals. Selective deafness is probably typical though
Milo has always been very strong willed even from a pup, but we work with it. You get to know your dog and you learn what works and what doesn't. I am under no illusion, Milo has been really hard work in ways my previous dogs havent but then he has been really easy in ways they weren't ie house training, walking on lead, learning commands in a nano-second. Its all swings and roundabouts I think.