Moving along and execution are important no problem. It does not have to be at the cost of thinking. Entrepreneurs are doers, and the reasons discussed are good. However, it won’t hurt to pause from time to time to think.
Startups are all about execution. Sometimes I encounter self-proclaimed entrepreneurs who have been “thinking” about a concept for many years, and haven’t started yet. Some of these may be visionaries, but none are real entrepreneurs.
You find out what works and what doesn’t. If you never act, you will never know if you are right or wrong. Acting leads to a market reaction, which could take you in another direction. As you act, you can find people to come along with you. As you act, you can find ways to do things faster, cheaper, better. If you act, you learn from other people.