I can not find whom this quote should be attributed to. But this quote i can relate to in more than a way.
When you overthink everything, you end up hurting yourself
When i was much younger, i used to overthink everything. This made me miss out on a lot of fun and opportunities in life. It also made me have an introvert approach to friendship and social events. Since many years, i have been successfully fighting this tendency, with varied level of success. My father has this exact same tendency, however he has never considered it an issue that need to be addressed. As a result, my father overthink-ed and over-analysed what people said, as well as business opportunities, making each opportunity seam too risky. As a result, he avoided many opportunities in life. Things become even worse if you overthink what people say. It is a waste of brain power, time and a trigger for conflicts.
Do not overthink, because you can not control all factors.
In life and business there are a lot of factors you can not control, including luck. You also can not accurately estimate the level of success you can achieve. You can not accurately estimate the number of customers or the potential amount of customers. And lastly, you need to factor marketing and advertising. All this to say, that in business, especially small business, you have to take a risk, if you overthink you would never launch your business.
In business, overthinking can lead to procrastination, and eventually to just scrapping off the plan all together. Thus it is best to take a risk even when not totally ready, because as Harry Tuman said: Imperfect action is better than perfect inaction.