Male almost 6 months old puppy has a nasty habit of biting me if he doesn't get the attention, treats or toys he thinks he deserves. I have been using reward based clicker training and he has responded really well. Walks beautifully in heel position whether I'm running or walking slowly with baby buggy, sits, lies down, stands and stays in position until released, walks between my legs military style, knows a bunch of fun tricks and he's lovely with every one etc etc but every now and again he gets a bee in his bonnet and will just randomly attack me. Mainly if he is free in the house with nothing to do, he will just come over to me and start gnawing on me. Or on walks from immaculate behavior to jumping up and biting my arm for no apparent reason. Is this normal puppy soon adolescent behavior? He's shed all his puppy teeth. On walks I correct by snapping his collar back when he tries to jump and bite and telling him no but otherwise ignoring him. Inside he gets put away in a pen. He sleeps in a crate at night and I worry that he gets too much confined time because we rely on the pen to keep him switched off when we have our hands full with other things. He's outside walking or playing for about 3 hours per day and maybe has 1 or 2 hours total of free time inside. Welcome suggestions and experiences!