To bide your time for revenge.
Just a as oats sets when cooled and is easier to eat, so is a clmly and long calculated vengence with no recorse.
Common proverb "porridge is best served cold"
"Dakota waited three years to venge his fathers death, it was porridge"
"Porridge! i tell ya, porridge!. Dont do it now, wait for it, you want it to be sweeter dont you?, the crab can wait"