An idol is a form of positive belief which flowers in the purity of the heart of the believer and the purity of heart is achieved when one loses his or her ego.
The Ego, Aham, is a false sense of identity.
Ego is a self-created image of oneself that could be higher or lower than what really is. When one considers himself or herself superior or inferior, it could be said that the person is in the influence of the Ego. In terms of spirituality, Ego is separateness from the God or source of life. The more one in tune with his true identity, the less the person will be in the influence of Ego.
Idol worship is not understood properly in the present era due to a lack of awareness about the significance and processes of worshipping.
An idol is created and located in such a manner with the help of deep science that it induces positive emotions because of perceived non-judgmental acceptance by the deity. If we look deep into it, one could realize that it is our own acceptance which we experience through the form of the deity.
Temple is an open space; anyone can come and bow down to the deity. When someone surrenders his ego and bow down, he in some way surrender oneself to the deity.
This is a mere process of giving up all worldly inhibitions and losing oneself to the supreme almighty, in order to be closer to who we really are.
Although science has advanced so far, life is still a mysterious phenomenon. We try to control our lives but there are times when we cannot control. Every incident has multiple factors, one can control a few numbers of factors but no one can control all or predict the future. The uncertainty of life could drive people crazy. So, when one surrenders the control to the deity, he or she gets out of the desire of control. One relaxes into the moment of awareness and this natural relaxation gives strength, the strength which was getting lost in trying to control life. When this strength releases from the grip of ego or control, it turns into creativity.
In ancient Hindu scriptures, the head is considered as the seat of ego or pride, so allegorically when one touches his or her head or chest before the idol is an allegorical act of yielding ego.
Now imagine millions of people coming and surrendering themselves towards the Deity, you can imagine the positivity of the environment, it will multifold every day. Thus, the process of bowing head down to the almighty is essentially helping us gain a positive energy, to help us let go of what is holding us down and find newer strengths to conquer our lives.