"When he has penetrated into hostile territory, but to no great distance, it is facile ground."
"When your army has crossed the border, you should burn your boats and bridges, in order to make it clear to everybody that you have no hankering after home."
Sun Tzu wrote in the context of war... but I'm sure it happened to you in your personal or professional life.
You dream of what you want to be, you get to work and then opportunity rings at your door.
You then step in a world not familiar to you, you have just crossed the border.
Then change is harder than what you thought, and you just want to go back at home doing what you are comfortable with.
Sun Tzu acknowledges that the solution is not to become fearless, courageous, detached, and disciplined. The best solution is to give you no choice but moving forward.
What are the boats you can burn now, so you have no way to go back when times will be hard ?