My 11 month old lab mix has started acting aggressive towards other dogs when she is on leash. She has been very well socialized with other dogs from early on. Most of her socialization has been off-leash, whether in a fenced yard or the dog park. I was sitting outside yesterday, with Marley on her leash, and a friend walked by with her little white dog. The dog came up to see Marley and Marley lunged towards her. I pulled her back and had her sit. That was the end of it but I've seen that behavior other times as well. It's only been on leash, when another dog greets her face to face. We could walk side by side with no problems. It's possible I tense up when other people want their dogs to meet mine while on leash. I should just say no but I was wondering if there is anything else I can do? I've heard that dogs greeting face to face is conisdered rude for a dog. Could that be bothering her?