Finding your why is a recommendation of many books, experts, mental health professionals, coaches, employers, leaders, etc. However, I believe, as well as many others, that you may not find your true why until you dig a little deeper. And this is where the exercise "7 Levels Deep" comes into play. I learned this exercise from an interview I heard with Dean Graziosi. By asking yourself a question about the previous answer 7 times, you truly are able to get into the core of what your true WHY is. Once you figure this out, you should use this WHY to come back to when faced with adversity, obstacles, or negative situations (even if it is to be a team member of the Avengers).
Below is my example for why I Spartan Race. (be advised that the deeper you go, the more emotional and vulnerable it gets). Especially when you are interviewed by someone.
Check out this site to perform a similar test on yourself. They use a different question system asking "why each level is important to you", which has a similar effect.
"He who has a why to live can bear almost any how."