Theodore Roosevelt from a 1910 speech given in Paris, an analogy to today’s entrepreneurs:
It is not the critic who counts; not the man who points out how the strong man stumbles, or where the doer of deeds could have done them better. The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood; who strives valiantly; who errs, who comes short again and again, because there is no effort without error and shortcoming; but who does actually strive to do the deeds; who knows great enthusiasms, the great devotions; who spends himself in a worthy cause; who at the best knows in the end the triumph of high achievement, and who at the worst, if he fails, at least fails while daring greatly, so that his place shall never be with those cold and timid souls who neither know victory nor defeat.
if you are an entrepreneur, forget the naysayers and just do what your heart tells you to do. you may be wasting your time, but at least you got into the arena. and if you fail, make sure you fail while “daring greatly.” Then, get into the arena again, having learned from your mistakes.