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.