I have opinions on most topics. At time quite strong, often - at least I hope - weekly held. Given that what I do consists in large part in thinking about product ideas, I also have a lot of opinions about what would work, and wouldn't, in a wide range of markets.
It's both a blessing and a sin. Every time I meet an entrepreneur working on a new product, I fall inevitably in the confirmation trap. Is she working on the angle I think would work? It's a terrible way of judging other people's ideas, and yet a very human one. I understand much better now the difference between a good investor and a rookie: the rookie will pretend - consciously or not - to know more than the entrepreneurs and seek teams that fit in his or her frame, the good one instead will remain objective, and open-minded, and let the entrepreneur show the way. Entrepreneurs are the ones creating the future.
There is a consequence to this. A good investor will inevitably tend to be sceptical and will try to underpin her judgment by looking for facts. The team's track record, usage metrics, growth, etc. Investors are patient and often prefer to wait precisely because they understand that their judgment - everyone's judgement - is easily biased.
But what to do when you can't wait? If you are a founder, or a co-founder, or an investor that wants to get in before any solid fact reaches the table, the only thing you have left is vision. Conscious of my bias, I will be happy taking a risk if it means following my vision. Right or wrong, it is at least mine. The only alternative is to buy into someone else's - and thus make it mine.
So this is my decision criteria in these situations: it's either my vision or yours, in all other cases I'd rather wait.