When lack of structure fails, it fails all at once. What works totally fine from 0-20 employees, is disastrous at 30.
You want an idea that not many other people are working on, and it's okay if it doesn't sound big at first.
Good startups usually take 10 years.
Before product/market fit, your only job that matters is to build a great product.
You should be able to describe any employee as an animal at what they do.
The best ideas often look terrible at the beginning the truly good ideas, don't seem like they're worth stealing.