Brazilian Jiujitsu
I've done martial arts (taekwondo, boxing, jiujitsu) for 10+ years now, and attribute much of who I am to the humbling lessons I have learned on the mats.
I'm a proud Blue Belt Brazilian Jiujitsu Practicioner from @ZionBjj under my good Mestre Renan Chavez. He taught me a very important lesson, he always says: "Nada regalao", which translates to "Earned. Never given".
The world is made up of people with either killer instincts or without killer instincts and the people that seem to emerge all the time, it doesn't mean they are the best people and it doesn't mean they are the happiest people and in fact in many cases and in most cases they are probably not. But the people that seem to emerge are the people that are competitive and driven and with a certain instinct to win.