I recently adopted a 1 year old pitbull (I know, to most the title of this thread will now make sense) from the humane society, and she is an absolute sweetheart... 90% of the time. I've had issues with her showing aggression on 4 or 5 separate occasions. All situations were men, and all situations involved someone coming into "her territory" (my house, my office, my pickup). Once she warms up to people, she's extremely affectionate, but I've now witnessed her snap at a friend, warm up to him, and then snap at him again when he came over a second time.
With all of this being said, I want to do everything I can to keep her, but am not blind to the issue and realize that not every dog is the right fit (and that I'm guilty of trying to rationalize her actions in order to make it acceptable). Ultimately I fear that if I have to go through with returning her it will be a death sentence. So I want to give her every chance to change behavior, but also realize any dog-attack story you hear the owner claim they never could expect it to happen. Have any of you dealt with a similar issue and if so, how did you go about addressing it? Whether it be training, kenneling when any company came over, taking to a shelter, etc.
TL;DR: Adopted a dog that show's aggression toward certain people on occasion. How can I fix it or is returning the pup inevitable/for the best?