Puja means worshipping the almighty Divine powers, Puja is the showing of your reverence to the God , Puja is an act of having a connection to the divine...

During the Puja the deity's cosmic energy is prayed to be come down through the chanting of Mantras, during thousand and thousand years people are realising the existence of God in this way. There is a big science and a spiritual science behind this which is not openly talked.
When People do puja (Aradhana) with belief in mind they get a faster spiritual effect or result like : peace and happiness in mind, peace at home (griha shanti) and workplace, protection from evil forces, Black magic, miseries, fulfillment of desires,sucsess in business, and spiritual benefits. In shastras lot of pujas has given For prosperity, material abundance (money and wealth), spiritual prosperity, speedy recovery from illness, To remove troubles that prevent us from starting a spiritual path or business, For getting married, For a smooth life, peace and harmony in the family, to improve family relations, for sustaining the family, etc ....
the Puja is also done to remove obstacles and negative vibration around a person and family and work places that hinders the progress and prosperity, Business Losses, distress etc…
By offering Puja to our God and Goddess a person get connected with this super power. Puja is basically a powerful spiritual procedure if it is done properly a person may get it's result sitting thousands of miles away from the place where puja has performed ,puja can be done by own or by learned vedic priest. If you can not come physically to the very places where the puja is going to take place then it is further better if you get someone who honestly offer Puja on behalf of you in a particular way, although you may not be present there at the time of your Puja.
Puja makes our body and mind holy and pure. It keeps our unrest mind cool. Puja is also the unconditional surrender of ourselves ...OUR BODY AND SOUL to the divine power which took pity on us, put mercy and wash away all our sins and teaches us from our within what to do and what not to do. Puja in many times fulfill our desires ...rescue from the dangers ...bring us to the point of prosperity ...and give us a glimpse of touches of blessings of the deity which fill up our body and mind with a different feeling and give rise an eternal peace. Puja gives us the strength to confront with adverse situation and get the victory.
Puja is a yoga ...Puja is a meditation which connect us with the divine (Jeeva with Shiva).

Benefits of a Puja
According to our sacred texts, Puja -
• Disciplines the mind
• Energizes the deity and the worshipper
• Enables one to experience oneness with divinity as we unconsciously offer the self through our material offerings.
• Puja establishes a bridge between the worshipper (the lover) and the deity (the loved). It facilitates flow of love-energy in both ways. This energy not only sanctifies the self but also re-vitalizes the body's resources, making one experience, what is called HOLY BLISS. Thus both the worshipped and the worshipper benefit from Puja.