In case you didn't know.. I'm sort of a fan of David Goggins. (The guy on the right)
I'll be brief because this doesn't need a whole lot of words.
Take this rule into your life. Remember it. Use it. Say it. Practice it. Whatever you can do, to never forget this rule. Do it.
When I first heard this it absolutely set me on fire, and drove me to push way harder in everything that I do and I constantly remind myself of this rule as often as possible.
In an interview I heard David Goggins say his 40% rule, which is this:
When you feel like you have given 100%, you're totally dead, completely exhausted, and given everything you can possibly give mentally, emotionally, and physically..
the truth is you're really only at 40%.
Learn more on this:
Article: The Hustle - The 40% rule
https://thehustle.co/40-percent-rule-navy-seal-secret-mental-toughness
Article: Forbes - The 40% rule
https://www.forbes.com/sites/chrismyers/2017/10/06/the-40-rule-the-simple-secret-to-success/#20b7eb6c5cdd
Video: Interview with Jesse Itzler who invited Goggins to live with him for 30 days https://www.youtube.com/watch?v=9I_u4oZqF8c