No you are not paranoid, supermarkets are stressful places to be. I avoid shopping on weekends if I can possibly help it, or when school lets out, usually, 9 a.m. to 3 p.m. is pretty decent. Not many people shopping, just staff restocking the shelves. You can wheel your cart around freely, select what you need, get in, get out, fast. Cannot guarantee there won't be some crying babies but most of the time it is a pretty calm place and time to shop.
Forget about the Big Box stores, I hate Costco. And I don't know how it is where you live but I love the self check out option, no cashier to deal with, and usually faster. I also prefer the same supermarket, I know where all the food items are that I buy regularly. It was a major trauma when the store decided to redesign the floor one time. If you are a night owl then I guess after 9 p.m. would be good too.
And yes there are days I would rather eat pasta, again, then go to the supermarket.....