Change the world. Build a business. Have fun.
Failure of your company is not failure in life. Failure in your relationships is.
Hard things are valuable; easy things are not so valuable. Reaching the mountaintop is rewarding because it is hard. If it was easy, everybody would do it.
The things that keep nagging at you are the ones worth exploring.
Assume the best but hire paranoid people.
Marketing, when done well, is about story telling.