Product managers by themselves are completely useless. We don't build products, we don't ship products, we don't sell products, and while we might occasionally do some customer support, that's not our primary responsibility. Our primary responsibility is to act as an interface between many stakeholders shaping up the product and coming up with a coherent story that everybody can relate to. The closest analogy for a product manager that I can think of is that of a politician. While in principle our main constituency are end users of our product, there are many other forces which must be accounted for, just like a politician must cater not just to voters but to many other groups of influence if he or she wants to hold on his or her chair. Just like in the case of a politician, communication skills are essential for the success of a product manager. If you don't like spending most of your days communicating with various stakeholders, you better not choose a career of a product manager or a politician. Communication and integration of different viewpoints and ideas is what we do for living, and while we might have an agenda of our own it is usually more of a detriment for our success than a boon.