A human being has a need for feeling valued and recognized. This need extends to people who are already successful and surprisingly even to those who are enlightened!
This means we can touch people by offering sincere praise and appreciation at every opportunity. By so doing you make a positive difference to others and at the same time, you feel good about doing so.
The catch is to be sincere and not do it because you want something back. If you are not sincere people will know and feel it. If you are needy in the process, it will appear that you have an ulterior motive.