Swami Vivekananda stressed on the positive attitudes of life- love, harmony, service and the like. Some of these concepts find echo in an emerging trend of psychological studies called Positive Psychology. In fact, most of these traits are considered as marks of spiritual wisdom.
The greatest religion is to be true to your own nature. Have faith in yourselves! If you do not exist, how can God or anybody else exist?
-Swami Vivekananda