With the various forms of Gods we believe and the trust of there is a super natural power named as 'God' who would make our life in this World a bit more happy and easy, we offer 'Puja' to 'God'... now, for a while let us keep aside the discussion of the existence or non-existence of God and let’s try to know why 'Puja' is offered to God in our tradition;

Puja (worship) of the gods consists of a range of ritual offerings and prayers typically performed either daily or on special days before an image of the deity, which may be in the form of a person or a symbol of the sacred presence. In its more developed forms, puja consists of a series of ritual stages beginning with personal purification and invocation of the god, followed by offerings of flowers, food, or other objects such as clothing, accompanied by fervent prayers.

Some dedicated worshipers perform these ceremonies daily at their home shrines; others travel to one or more temples to perform puja, alone or with the aid of temple priests who receive offerings and present these offerings to the gods. The gifts given to the gods become sacred through contact with their images or with their shrines, and may be received and used by worshipers as the grace (prasada) of the divine.

Sacred ash or saffron powder, for example, is often distributed after puja and smeared on the foreheads of devotees. In the absence of any of these ritual objects, however, puja may take the form of a simple prayer sent toward the image of the divine, and it is common to see people stop for a moment before roadside shrines to fold their hands and offer short invocations to the gods.

There are several forms of puja's that are performed in Hinduism like general puja in which Gods are worshipped to honor them. This type of puja can be performed on daily basis in the temples or within a person's heart. Then there is shanty puja, in this form of puja a havan is performed in the house. The main aim of this puja is reduce the worries and tensions that are hovering over a person's life. Shanty puja helps in decreasing the negative energies and helps a person gain back his confidence and live his life peacefully. This form of puja can also be performed on the demise of a person in a household to make his soul rest in peace.

Graha Puja is usually done before entering in a new house so that a person can lead a happy and healthy life in his new house. This puja helps in bringing positive energy inside the house and allows people moving in to commence a new life and stay happily in it.

Event puja is a puja that is performed during different events happening in a person's life. This puja can be carried every year to honor the person on the date of his death. It can also be performed to celebrate some happiness or achievement every year. Tithi puja as the name suggests is performed on a particular tithi or date. The date can be of any importance to a person and can be performed at different times of the year.

Then there are puja's for health and wealth as well. These puja's are performed with various mantras and rituals that helps in promoting good health and wealth in a person's life. A person who is struggling hard can open new opportunities and reduce his hardships by performing this type of puja.
When you believe performing Puja giving you a positive energy more than anything else, then why having second thoughts in doing so?