There are only two types of things in the world.

There are only two types of things in the world: Things you can change and things you can't change.
Your boss is likely things you can't change. All the things he criticizes you are things you can change.

If you spend time on things you can't change, you'll become angry, frustrated, bitter and depressed. If you spend time on things you can change, you'll have greatly improved yourself for many years to come. It is your choice, an important choice of your attitude toward life.