I try so hard to do anything to please. I do not say much because it will be my fault.Even asking why she was angry was the wrong question to ask. I was very calm when I posed the question. She became irate. Saying I must never criticize her. Tirade lasted over a hour. This happens more days than not.
Your person's brain is broken so now you are the only one who can adjust to avoid blow-ups. You didn't cause her disease and you can't fix it. It is progressive, so will only get worse. You must think carefully now about your future, so that you have options to hand over caregiving responsibilities to a facility, or just resign and leave this situation in as clean a way as possible.
Your next act today would be to call this person's doctor to get meds for their depression/aggitation/aggression/anxiety. My Mom is on the lowest dose of Lexapro and it helped her a lot.
Perhaps educating yourself more about dementia will better help you understand what is going on with your loved one and also help you not to take things so personally.
Your loved ones brain is broken and will never get better only worse, so it's time to just go with the flow or if that's too much for you look into getting her placed in the appropriate facility.
The way you are feeling now, it sounds to me like this is beyond your ability to manage. Please ask her doctor for medication. If this continues, it is not sustainable long term for you. Please consider placement in an appropriate care home.
You have Dementia as the topic. Stop trying. Try to ignore. Its the desease. Ask her doctor for a medication that may help.