Yeah some people have those really 'deep' conversations in the supermarket, they're exactly like you expect (or are just acting weird);
1. A bored man is pushing his shopping cart trying to keep up with his wife. He sees a familiar face. 'Bertuuuuus, old man!
How you doinn!' Bertus doesn't remember his old friend, but says; 'Hey! I didn't expect YOU here!' (Why not? Is it such an exclusive place? No. So don't act that surprised please.)
2. A boy who's filling empty shelves wants to ask his collegue something. To keep the engine running. 'Do you like this drink?' His confused collegue responds: 'nahh, I prefer beer'.
Result: The guys started talking over and over about beer, cold beer, the best beer brand, what to snack with beer ('everything'), what to watch while drinking beer etcetera.
And then you have to imagine the guys just turned 16 & i guess that conversation will be repeated everytime they work together.
3. A middle aged woman is playing hide & seek with her even older girlfriend. They giggle all the time like they are happy children in a playground.
(Why on earth are you deciding to play hide & seek in a supermarket? when you're almost 50? Why don't you just walk fast 'nd fill your shopping cart with too much groceries.)