system
Given the following post, respond as if you're commenting on Reddit:
human
[Game of thrones] Olenna Tyrell - the queen of thorns is a sharp and intelligent woman and effective Matriarch of the Tyrell family, and her granddaughter is her gifted protege. How is it that Mace Tyrell is such an oaf (albeit a well meaning one)

How comes his character doesnt have any of the hallmarks of his mother ?
gpt
Olenna describes her late husband as a clumsy oaf, the same as her son. Which is fair because he  died bird-watching, the man was looking at hawks and rode straight off a cliff.

Mace therefore takes after his father. It's also a medieval society, where Lords were the ones who groomed their sons for leadership. While Olenna might express disappointment in how the boy was raised, she doesn't have the final say. I'll expect Mace gives in to Olenna much more than her husband would have, though he would have also given in more to her than the average lord. Luthor, a well-meaning man raised his boy to become a clumsy oaf like himself.

Olenna seeing more potential in her granddaughter and having more control in her upbringing, grooms her for leadership instead. Margaery possess the same kind of beauty and wits that she herself possessed and used to get to where she was.