{I told the story of Joseph to the children as a Bible story (A Bible ‘Soapie’) as a way of seeing that bad things can happen to good people (see Genesis Ch.37 to Chapter 50) but God was arranging things because He knew what was best.}
In listening to the story I think your feelings for Joseph got mixed up with the real story. Joseph is never reported as being angry with his brothers for selling him to slavery in Egypt (I would have been!).
Somehow Joseph, perhaps knew to trust God and not show anger because God was with him and, well, ‘arranging things’ so that one day Joseph would be standing before the Pharaoh. Joseph would explain the two dreams to him – dreams that nobody else could interpret (the 7 cows and 7 corn plants) and then for Pharaoh to appoint Joseph to be governor: “Second to me only in all Egypt.” And the work of storing up all excess grain to sustain Egypt in the seven years of drought (famine) that was to come later. The Pharaoh was extremely glad to have Joseph there – he saved Egypt from starvation. I like the story because bad things do – yes, still today – happen to good people.