a slice
Examples
For me, the cinema is not a slice of life, but a piece of cake.
He looked as inconspicuous as a tarantula on a slice of angel food.
Compromise, hell! That's what happened to us all down the line -- and that's the very cause of our woes. If freedom is right and tyranny is wrong, why should those who believe in freedom treat it as if it were a roll of bologna to be bartered a slice at a time?
A lot of movies are about life, mine are like a slice of cake.
Who is over nice, loses many a slice.
You never miss a slice from a cut loaf.