I love JiuJitsu because many parts of it are like microcosms of life. The first time someone lays on you and you feel like you can't breath, you panic. That's an emotion. After a few times you realize you can breath and eventually you will feel the panic and instead of succumbing, it'll wash past you. By practicing feeling emotions, especially negative ones like being uncomfortable over and over, eventually they move into your higher level thinking and no longer control you. You absolutely still have them, but your reaction to them has changed.
Thats different from actually being choked and tapping to end the fight.
Also, BJJ has been one of the biggest unlocks in my personal growth and stoicism journey. Things that used to make me uncomfortable or annoy me in daily simply don’t. I’m not externalizing my negative emotions, I’ve just become better at dealing with them through repeated challenges. Early on my teacher told me that everyone loses, but the difference between white and black belts is the black will be calm thinking how to escape until the very end. Contrast the white belt who loses control and flails around accomplishing nothing.
For example, anxiety exists and sometimes occurs, and it means parts of me are trying to be very careful and precise about something. This can be a problem at times if it overcomes you, but it can also be leveraged into a strength once you figure why it's flaring up at the moment.
Another example, travel used to be a nuisance, but now I've setup and continue refining some packing and preparation checklists for trips of varying length. Now it's a big no-brainer to be well-prepared for a short work-trip and I'm usually very calm about it.