I've said this before, so if you've already read about my boxer you can skip this part: about a month ago, my family adopted an approximately 3 y/o boxer girl, Sasha. Because of her teats and health, the vet said that she has probably already had two litters of puppies. She came to us 15 pounds underweight, recently spayed, and completely ignorant; she didn't know her name or a single command. She now knows a few basics, but none of them with great reliability. At her last trip to the vet, about 2 weeks ago, I did something stupid: I let her walk ahead of me on the leash into the vet's office without going first. Another dog was in there with her owner, a large pit bull mix. The owner said that her dog doesn't like other dogs, and they were growling at each other and I had to pull Sasha away. Luckily, she is a small girl and not very strong, so I can easily pull her away from a bad situation when she is on her leash. I had to stand between her and the other dog, as Sasha was staring her down and growling now and then. Before that time, her impolite staring has been a problem. When confronted with a strange dog, she will plant her feet and fix the dog with an intense stare that scares most other dogs. She becomes intently focused on the dog; she will rarely eat in front of strange dogs, and mostly my commands fall on deaf ears. I should also mention that we have a bossy 10-year-old Chihuahua at home who is used to sharing her home, but isn't thrilled about it. Once or twice Bambi has been her bossy self and growled at Sasha, and Sasha growled back, but has never, ever tried to hurt her. Now she likes Bambi and will try to play with her, and Bambi in turn tolerates Sasha. We have no problems with them. Since the vet incident, I've really been worried about her potential aggression issues. I take her to Petsmart a few times a week (she cannot handle Texas summers, so walking her usually doesn't work out well.) She occasionally gives a very low, quiet growl to other dogs. She does not hide or pull away from them; she instead pulls on her leash and tries to get to other dogs. We let her meet a male Shar Pei face to face, and Sasha stood very still while the strange dog sniffed all over her face. She tolerated it for a few seconds before she began to growl and I pulled her away. Then we had a breakthrough, in the form of a small male dog about half her size. I got down on my knees and wrapped an arm around Sasha so that I could pull her back if I needed, and I let the dog approach. Sasha stood stock still as the little dog licked all over her face, her ears, etc. After a while of tense tolerance, she bent down and licked the dog on the face. I nearly died. But things got worse later on: I let a 6-month-old bouncy, exuberant Boxer puppy (female) approach her, and she gave a loud, snarling bark and started to lunge at the other dog until I pulled her back. I'd never heard her make that sound or seen her react that way. She's a perfectly behaved lady with people: she politely stands back and lets people approach her first, then soaks up the love. I have some offers from friends to help with socialization, but I need pointers. How do I reduce her anxiety and eliminate this aggression? Does it sound fear or dominance-motivated? Thanks in advance for any tips.