If you want to be a bad product manager, provide as many ways as possible for customers to buy your product. If you want to be a good product manager, provide a reasonable but limited set of ways for customers to buy your product.

If you want to be a bad product manager, listen to customers only through surrogates. If you want to be a good product manager, listen to customers in person.

If you want to be a bad product manager, react to every customer. If you want to be a good product manager, understand the market.

If you want to be a bad product manager, only focus on the short-term. If you want to be a good product manager, think in context of the long-term.

If you want to be a bad product manager, define the scope of your product as how you see it. If you want to be a good product manager, define the scope of your product as how the market sees it.

If you want to be a bad product manager, hoard information. If you want to be a good product manager, share your knowledge.