Since I meet with many product managers, I’ll start here. The worst phase to join for a product manager is the “drunken walk”. Don’t do it, you’ll be miserable. If you are attracted to early stage challenge, found a company or become an engineer. Otherwise you will wrestle with the founders for control of the product. Or you’ll conclude the founders shouldn’t be in charge and you will want founder compensation for finding product fit. Both are bad outcomes, leading to sadness.