[Twirrim]

I've been lucky to work with a series of really good product managers, with one exception who thankfully didn't last long enough to do too much damage (though he did result in me having to attend the single most awkward meeting I've ever had to attend, where right from the top, and throughout the entire hour, he was demonstrating to his skip level manager that he really didn't understand the product at all, and the skip level did).

They help us out a lot by understanding what the customers want, what we can provide, what time lines are sane, handling interacting with legal and business interests galore, and I help them out when they need to check in on technical sides of things. Teams rarely lack for ideas of things they can build, ways they can improve the product or operational experience. A product manager tries to make sure you build the right thing.