Last Spring my husband and I adopted Nigel, a 2 yr old Corgi. He's an affectionate, smart and (mostly) obedient boy. The problem is he has an aggressive streak. He THROWS himself at the glass door when anyone (including my husband and I) come to the door. He barks and growls at anything that he deems unusual or out of place especially on walks, and he goes crazy when he sees or hears children or other dogs. I worry he may bite someone one day. We've done obedience training, but this problem has not been adequately addressed. We use positive reinforcement for good behavior and "corrections" for negative behavior. I feel confident he respects me and my husband. Can anyone offer any specific suggestions?