I think that all the members here are dog lovers. And I'm not an exception. A few months ago, I adopted a 2-year-old labrador. I don't know why, but he was aggressive at the beginning. It was strange because that bread is friendly and calm. He ruined some things in our house and was aggressive towards other people, and sometimes, when I tried to stop him, he was so aggressive towards me. Maybe, the previous owners mistreated him. It was scary, but I'm responsible for everything, so I took him into a school, where the well-trained person worked with him. Also, I started to look for any info, how to behave with such a dog, and help him to change that behavior. I know that many people face aggression when they take a new pet from former owners. I don't have enough rights to suggest something, but from my experience, I can say that the best way is to find out the reason for such behavior. And after it is easier to work on it. In this post, there is a lot of useful information on dealing with aggressive dogs and those who have behavioral troubles. It helped me, and I do hope that it will help someone.