Tony Xu of @DoorDash on getting rejected by investors, competing against rivals with thousands of times more capital, and how founders can tell conviction from delusion: "I had over 100 rejections in a span of over 1,000 days where the company almost constantly ran out of money... I couldn't raise a dime, and we were running out of capital." "Companies like Amazon or Uber were in the space who had way more capital than we had. Hundreds of times, maybe thousands of times of capital deployed…