While Mary’s anger at Brenda in Young Sheldon season 6 makes sense, this fight also sets up The Big Bang Theory character’s gradual devolution. Young Sheldon’s Mary has a lot in common with her incarnation in The Big Bang Theory, but the younger version of the character is also different in some important ways. Young Sheldon’s Mary is less bitter than her The Big Bang Theory self and her worldview is more optimistic. While she is prone to scolding, she is not the angry figure seen in The Big Bang Theory and this could be because the early death of her husband George Sr left her feeling despondent.

However, much like Young Sheldon season 6’s Missy plot proves that Sheldon’s sister never wanted a staid life even in her adolescence, the outing is also proving that Mary’s bitterness could predate George Sr’s death. In...