People only change when they want to change. You can reason with them, yell at them, even leave them. The only thing that makes them change is their own realisation that they need to change.
You can go to the gym, drink your water and eat right, but if you don’t deal with the shit going on in your heart and head you’re still going to be unhealthy.
Forgive the person and their actions, never give in to hate, let it go, set it free, and karma will take care of what is meant to be.
You can’t expect yourself to go from a negative mentality to a positive one overnight, but every time you correct a bad thought you are growing! So focus on your growth, not the fact that you aren’t there yet.
Most humans are never fully present in the now because unconsciously they believe that the next moment must be more important than this one. But then you miss your whole life, so be in the now.