It seems like Mom's angry outbursts are tied to her frustrations over not being able to do the things she's always done. I think it's her way of dealing with her loss of independence. Don't get me wrong, so far they are few and far between with me, but I remember the first few months of living together and the hallucinations, the anger and the other weirdness that is Alzheimer's.
Yesterday I made a quick run to the Home Depot. When I came home Mom told me something about a man stopping over. I was concerned about this and quizzed her, then I forgot about it chalking it up to the disease and confusion. Tonight George mentioned that the garage door was up and the car was missing and he was concerned so he stopped over to make sure things were OK. Mystery solved. It's nice to have neighbors who care. I must have pressed the button to close the garage door but it didn't go down. Hmm.