Naw you are not old, 40 is young otherwise I would be as old as the Mayflower, lol. No, you are not getting mean or ornery and being cooped up in the house has nothing to do with it and your CP has nothing to do with it. You have something many people do not have "common sense". I know many intelligent (book wise) people, but, they are totally ignorant because they have no common sense. If a person has no common sense then they are ignorant.
I have to add my two cents on grocery shopping and shopping in general. I hate going to the grocery store, why, its the people that stop their cart in the middle of the aisle so no one can get thru and they stand there and scratch trying to read the labels and decide what to buy. Or they run into an old friend and want to hold "old home week" in the middle of the aisle. Drives me nuts. I very loudly will say excuse me. Or what about the one at the cashier checking out and she is almost finished and remembers she forgot an item or two and she runs to get her items. She holds up the cashier who can't say a word to the customer because they are always right. So, she is being held up and so are the rest of the customers. I try to shop either very early in the morning or very late at night to not have to be around these people. My children refuse to take me shopping, they call me the shopper from hell. The only one brave enough to take my is my poor daughter-in-law she gets stuck with the old bat.
The ladies at the mall are brutal. Between carrying those big suitcases for purses and knocking the hell out of you with one of them or the ones with little kids in strollers and hitting you with them, we can't win. Thats why I shop online.
But, in my defense I do have a nice side that comes out in the grocery store. If I have a lot of items in my cart and someone comes up behind me with only a couple of things, I always let them go ahead of me so they can get out there. That always brings a smile and a thank you.