I often suggest this practice: try for just one week to be completely selfless. Do every action as a service. “For the whole week, let me be selfless. Let me always give, give, give and love, love, love.” If you really don’t get any benefit, if you don’t enjoy that week, you can go back to your old way. But if you get even a taste of the joy of giving for the sake of giving, you will love it, and you will look for opportunities to taste it again and again. I guarantee it.
Everybody should set aside some time for this, just to get a taste of that joy. Then you can expand it more and more. That is the trick of Karma Yoga. When you do everything for the sake of doing, for the joy of doing, as a dedicated act for the benefit of the whole world and not just for your benefit, you retain your joy. Don’t ever think that you get joy by doing. The joy is in you always. By keeping the heart pure through loving and giving, you retain the awareness of that joy.