Tranche de vie is a French phrase that means "slice of life". In literature it refers to a storytelling technique where a character does seemingly arbitrary everyday things in a plot with little or no conflict.
This is a weird literary device, and I don't see it used a whole lot. I think most modern writers learn young "must have plot" and not necessarily "must-have theme". Plenty of stories are meant to be enjoyed and not necessarily analyzed. But on the rare occasion tranche de vie pops up, I get to ask the fun question: What does it mean?
Sometimes it means the story is incredibly well-thought-out; the author is using an arbitrary and otherwise dull moment in a person's life to illustrate a point. Sometimes it means the opposite: the author simply got carried away and had no point except that he didn't know how to end one scene and move onto the next.
If little else, tranche de vie offers an opportunity stop and think, to complement or critique.