The old saying "Two cooks in one kitchen never works" is so true! It's your mother's home and she likes things where they are for a reason. It could be as simple as she enjoys where she has put something like a chair, vase, etc., or, it's easier for her to get too. It is not your home! If she asks you to do something such as cook and you don't do things exactly as she would do it then yes, it's nagging and you should say, "Look, you asked me to cook and I'm doing it the way I know how and if you don't appreciate it then feel free to do the cooking yourself." The older people get the more habits they incur. They have set routines because it makes them feel comfortable. For a daughter or son living at home it could be upsetting for them. My sister-in-law's two sons moved out into their own basement suite. While mom meant well by bringing in bags of groceries she also took it upon herself to move the sugar bowl, spice rack and salt and pepper shakers and her sons complained because they couldn't find them! LOL Mom had every right to help out, but did not have the right to move anything the way the boys had placed things. The only suggestion I can give you is leave furniture, vases, etc., alone and leave it where your mother has placed them. This is her right. If she complains when she asks you to do something then it's time to sit down and communicate without yelling or fighting over it. The both of you should be able to come to some common ground.