Running 100 km is by no means easy feat, even for seasoned runners. Important thing to achieve one is - to first convince yourself that its possible. Then, it's all about making small progress everyday - run little longer every day. Then, your body understands rigor of it and gets ready gradually. Key is to understand limits of your body and mind, to push it without breaking down. It is not at all about optimism, rather about realism.
If you make small progress every day, you are ready for big run in couple of months. You start the race by looking around and trying to match other's pace. Then, you realize that you are really running against yourself. Upon it, you focus inwards and enjoy the body going through rhythm - slow and steady. When you finish the race, you yearn for more. That is how it goes - success feeds on success.
Most of the startups fail in first two years. You start with great idea with focussed execution. But forget concept of making small progress every day. You can not run 100 KM on your first day of training, unless your body is geared for such distances, so is the business. So, forget billion dollar valuations and focus on adding value to the customers every day, make every interaction on your platform count.
Afterall, entrepreneurship is endurance game. Slow and steady wins the race.