I like grocery shopping at night. There's a 24-hour Giant Eagle about 5 minutes away, which is great for when I have those "crap, I keep forgetting to unclog the shower drain, so I should go buy some stuff for that and do it right now" moments. The best time to go shopping is after 10 pm. There's no traffic, I always get a good parking space, and the employees are more laid back. The store is almost empty, so I don't get anxious around so many strangers. I can stroll along, humming and twitching if I want, and there are almost never screaming children in earshot. It's wonderful. I highly recommend it.
I also rarely go to Walmart before 10 pm (I rarely go there anyway, but still), because that store is like a nightmare in the day time. It's already a huge sensory overload as it is, but during the day, the store is full of 600-pound people with mullets and their entourages of 8 children, clogging the aisles. I can't stand being in there for more than 15 minutes during the day. But not at night. I'm more relaxed when there aren't many people around.