As per the mythology- Lord Ganesh is supposed to be going back to the higher dimensions to meet his father, Lord Shiva. Lord Ganesh rules the first chakra, Muladhara. This chakra is concerned with survival and our daily existence. Lord Shiva rules the higher chakras and particularly the seventh chakra (Sahasra) which signifies a completely awakened Kundalini (Shakti energy). The clay form of Lord Ganesh when he is visiting the earth (Karmic plane) indicates the mortal nature of man, which needs to be dissolved for spiritual transformation.
The day of Anant Chaturdashi signifies this awakening of our Kundalini energy. If we have been in-tune with the natural energies and Lord Ganesh; praying to him with true earnestness, then he will take us to our highest awakened self (an opened seventh chakra) and this transformation is the awakening and rising of the Kundalini energy.
It is interesting to note that the next fifteen days of the dark fortnight are called as the Pitru Paksha, where we are expected to pay off our ancestral karmic debt; our pitru-roon.
So our soul journey which started with paying obeisance and truthfully praying to Lord Ganesh now experiences transformation, which in turn awakens our Kundalini energy.
We then need to truly work with those Shakti energies (during Navratri), to victoriously transform ourselves!
Hopefully on this day of Anant Chaturdashi, Lord Ganesh will bless all of us with true understanding of our own real nature, our conscious self, so we can start the process of our transformation.