At times this film has the eager, sincere quality of a student play: excitable theatre kids giving it their all. But when heavier dramatic lifting is required, it falls short.

By focusing on life and its messiness instead of looming death, Hart’s film earns the emotion other cancer dramas take for granted.

Sandler is sweetly attuned to Sophie, a sometimes tentative teenager. And Lynskey strikes a believable balance as both a fighter and a woman tired of the fight.

"Don't Say Good Luck"...manages to avoid the worst inclinations of this kind of drama, instead giving us an earnest and heartfelt look at the realities of being a teenager losing a parent and a parent saying goodbye to their teenager.