Being an entrepreneur requires an immense amount of confidence. Whatever brand you are representing as a salesman or a business owner and especially as a startup, confidence is the number one most important quality to possess. When I started Traversify back in 2009, I listened to probably 100 people tell me that it wouldnt work. And whether they were right or not, it was so important to listen to what they were saying but to never give up.
I know its 2 years old but this video from Grasshopper always keeps me from giving up.
"You can trade your hours for dollar or your ideas for millions"