Slice of life is about things that matter in life. It's about shifting your perspective and appreciating the small things. The supermarket is a great example. It doesn't seems exciting but it's something we do often but don't think about doing often. The term defamiliarization comes to mind (see: https://en.wikipedia.org/wiki/Defamiliarization).

For people who haven't watched slice of life you should really watch azumanga daioh

Little bro’s clearly never witnessed the hilarity of Nichijou. I kinda feel bad for him.

Sauce

Any slice of life anime suggestions for someone that is only just now hearing about them?