When we adopted Raja at 9 months of age she had lead a fairly sad life. Her previous owner had gone through a separation shortly after adopting her (I know him, and feel sad about his situation) and began living the single life. Hence, Raja ended up in a crate a lot. He had young kids, and she is great with them, but...
We shortly after discovered that Raja occasionally takes an intermittent dislike to certain people. For example, my cousins came to visit one day. She was fine. Happy and smiley as usually. Suddenly, she began to growl at one of my 10 year old twin cousins (the one who would smell nothing like an animal as he as horrible allergies). Another day, we were on our way to the pet store to try to socialize her more and stopped to get gas. She began growling fiercely at woman at the pump next to us. She managed to hop out of the car and my husband had to use all of his strength to restrain her (I probably wouldn't have been able to to it). We ended up leaving her in the car when we got to the pet store (despite having other past successful trips, we didn't want to put other dogs and owners at risk).
She has not recently shown any problems, and we try to have people come over as when we invite them in, she is receptive (way too much so probably). The problem currently lies in that none of our friends are dog lovers, without along 140 pounds of slobbery dog love. My best friend, who tries, breaks out in rash where Raja's slobber hits her. Ideas? We are planning on getting her into another Obedience class (she knows her commands, but they don't seem to work when this aggression comes over her).