Miserable people focus on what they hate about their life. Happy people focus on what they love about their life.
Promote what you love instead of bashing what you hate.
Forgiveness takes the burden of hate, guilt, and bitterness off your back and, with a lighter load, you can climb higher and faster, and be much happier in the process.
It is impossible to go as high as you are capable of going, if you are carrying the burden of hate, revenge and bitterness.