Answer by Balaji Viswanathan:
Hinduism is about discovery, instead of a hand-me down approach towards finding truth. The various gods are representations of various attributes to concentrate upon. For instance, Shiva represents austerity, Lakshmi represents prosperity, Saraswati represents knowledge, Shakti represents valor and so on.
At the base level, we get to think and dwell about these various attributes in various times of the year. For instance, during Navrathri time we think of the various gods representing arts and valor. During Diwali we think of the Ram who represents equanimity and justice. During Chaturthi we think of the joys that Ganesh brings. And we celebrate each of those attributes in those forms. This adds variety to our life.
At the next level, we start forming, which is essentially the favorite god/quality to focus upon. Meera, for instance, focused all her energies on Krishna. Many others pick up Ganesh, Karthikeya, Shakti, etc. We are all different and thus we would react to some attributes better than others. For instance, I might like Saraswati more than Shakti as the attribute of knowledge is more dear to me. Hinduism provides these various options of which one might touch my heart the most.
In short, we don't think of all gods at once, but pick one from a range of options provided. Think of it like a school. When we are young, we are taught a range of subjects and as we grow up we start specializing on a particular branch based on our interests.
At the final level, our rishis would have pondered so much that they start seeing God in everything. The forms become immaterial to them.
There is an ancient Hindu story that Swami Vivekananda recounted once. There was a guru who took his disciples to a beach at night and tried to show them the various constellations. Whenever he had to show a constallation he had to point his finger up in that direction and the students would follow his finger to eventually see the constellation. Once they have found it, he no longer needed to keep his finger up. The role of various gods and murthis are the same. They help focus on a particular direction. And after we have found the truth, we don't need the form any longer.