If you want to be a bad product manager, don’t make any decisions until you’ve fully researched every possible angle and discussed its implications with all relevant stakeholders. Without that legwork up front, you risk making a bad decision, which would diminish how you as a product manager are viewed. For most decisions there isn’t a big rush, and you want to make sure you are positive that you’re making the right decision. You also need to make sure that everyone who could possibly be impacted by the change — internal and external — is consulted and has the opportunity to provide feedback. These sorts of things take time to research and discuss, but that’s okay, since everyone else can just sit back and wait for you — the product manager — to make the decision.
If you want to be a good product manager, be informed and decisive. Rather than waiting until an issue arises to research all of its angles, constantly keep your eyes on the ground and ears to the pulse. (I think I just mixed metaphors there, but go with me.) It’s never going to be possible to consider every facet and talk with everyone who might be impacted. Ultimately you are the one who is responsible and accountable, and consulting with others isn’t going to push that responsibility. The choice to not make a decision — to do more research, run the numbers again, talk with more customers — is actually a decision! In many cases, decisions can’t wait, and while you’re off gathering more information, the work goes on without you.
As a product manager, you will make bad decisions. I guarantee it. Good product managers make smart decisions based on the information they have and are not afraid to admit when a decision goes wrong. Most importantly, they’re constantly learning, looking at why the decision went wrong and how they can avoid that next time. You learn a lot more from experimenting and trying new things and sometimes failing then you do from always playing it safe.