Poojas and Chanting mantras are virtuous acts, they help in keeping the native nearer to God, thus reducing negative desires and gives merit. By doing puja, thoughts and vibrations of spiritual forces are created around us. These spiritual forces work to eliminate the negative influences in our life and help surround us with positive energy which can bring us peace of mind, material prosperity and enable us to more clearly touch the Divine, our true nature.
Pujas are traditionally performed in temples by residing priests trained in the exact science of puja including the precise details of auspicious times to do certain pujas, which mantras to chant, etc.