... for the top twenty most valuable YC companies, all of them have at least two founders.
You certainly don't need to have everything figured out in the path from here to world domination.
You really want to know your cofounders for a while, ideally years.
You have to be intense. This only comes from the CEO, this only comes from the founders.
Before product/market fit, your only job that matters is to build a great product.
You have to save the vision speeches for when the company is winning. When you're not winning, you just have to get momentum back.