One of the things he talked about, and something that I have both experienced and absolutely detested, is the way too many startups try to behave as if they were larger corporations.
Just as children are not and cannot be treated like little adults, startups are not and cannot be treated like little Fortune 500 companies.
The startup phase is the time to search for a business model. Emphasis on SEARCH. This is not the time to create a business plan and stick to it. This is the time to make a few guesses and then test test test, constantly seeking and listening to the feedback from current and potential customers.
As Steve said, "No business plan survives first contact with the customer". You can plan all you want, but never, ever let that plan paint you into a corner. For a startup to succeed it absolutely MUST be flexible, nimble, and quick to consider and embrace new possibilities and routes to income and profitability.
When a startup begins to behave like a large corporation, even though it is not a large corporation, that is essentially the kiss of death.
I've worked at a number of companies that have done exactly that, adopted policies and plans and approaches that were more suited to large companies than startups, and the employee pain and stifling of creativity were palpable.
So the lesson every startup should learn is this: If you are starting or thinking of starting a company, don't become rigid and inflexible right from the get go! Focus on creating a business model, not a business plan, and adapt and change and pivot as often as needed until you've found a model that is both scalable and repeatable.
Remember these words: Flexible, Scalable, Repeatable.
If your business model is flexible, scalable and repeatable, you've won.