Good Product Manager/Bad Product Manager

As written by Ben Horowitz in “The hard thing about hard things”

Good product managers know the market, the product, the product line and the
competition extremely well and operate from a strong basis of knowledge and
confidence. A good product manager is the CEO of the product. A good product
manager takes full responsibility and measures themselves in terms of the
success of the product. The are responsible for right product/right time and all
that entails. A good product manager knows the context going in (the company,
our revenue funding, competition, etc.), and they take responsibility for devising
and executing a winning plan (no excuses). […]