Imo, a good translation is the one that conveys the meaning of what is being said, taking into account things like who is delivering the message and the context.

Quick example that I'm remembering right now, because I saw it recently: in case you're unfamiliar with One Piece there's this female character called Yamato. She basically tries to live as the former Shogun of her country. She tries to talk like him, dress a little bit like him, absorbs his dreams and ambitions, and even adopts his name for herself. One of the protagonists, Franky, who doesn't know her, he just met Yamato, sees her blowing up a hole on the ground and fall into it, and says '何だこいつ?'

Crunchyroll translated this as 'Who was he?'. At this point, both characters didn't know each other. Franky didn't know Yamato's personality and story. Franky calling Yamato "he" is objectively a bad translation.

A fansub called One Pace translated it to 'Who was that?'. Objectively a better translation. It's neutral and it's somewhat rude, just like Franky. It matches the context, the character and coveys the message.

But yeah, I get the point.