Joss Whedon writes annoying dialogue
He is not a good show runner. He is not a good writer. What he does well, maybe better than anyone, is develop a fan base and pander to that dedicated base until they turn off their brains and just nod along. Also Firefly was OK, not grand, not amazing, just OK.
The Big Bang Theory is a nerd minstrel show.
The Big Bang Theory killed nerd culture and flooded everything I enjoy with normies who radically altered and overwhelmed each sub culture they invaded.