One lesson that I've learned in angel investing is pre-supposing what I would do in a certain situation instead of listening to the founder and what they're planning to do. This sounds somewhat obvious, but it's actually a bit more insidious than that.
As someone optimistic, it's easy to see the potential in a product and see how founders might try to seize that potential. That's not going to work. It's not going to work because your experience is not the same as theirs. Since their context differs, they're going to do different things. Those different things are going to lead the company down a different path. Success has path dependence.
It's easy to get excited when talking to a company, but if you're just assuming / pre-conceiving how they're going to enter a market or tackle a problem, you're likely setting yourself up for failure as an investor because you're not the one driving the company or the strategy - they are.
This happens in particular as an investor because I wanted to see the potential in companies. I only made the mistake once, so lesson learned and I'm writing about it here to ensure I don't make it again :).
I realized that this problem has carry over in to the product management and leadership domains. If you're hiring for a particular role (especially one with seniority) you're going to need them to structure their work and make decisions. If you're assuming what they're going to do, you're going to be "investing" in the wrong person. The issue becomes much more obvious when stated from this hiring perspective but the same principle holds.
I realized that this carries over to product management as well, albeit in a role switch. If you're assuming that engineers or others across the organization are going to make the right decisions without clear guidance (or instructions, depending on seniority), you're going to end up disappointed.
As a PM, in our planning processes and documents, we share context around how others should make decisions. As investors, we don't necessarily have that privilege, we just need to listen as to whether or not people are going to do what will be effective and what's 'defensible' or a moat about that particular plan of attack or approach.
This issue is evergreen and insidious, affecting organizations and investments. It's there unless you're looking out for it. Writing this down so I don't make the same mistake again.