People have various reasons to be with a Guru.

Broadly they can be put in these 5 catagories.

1. You would like to have your wishes fulfilled and because it is more pleasurable.
2. Everything else looks more painful to you and you come for comfort.
3. You want to evolve and become enlightened; you want to know higher Knowledge.
4. You have a vision or goal; you share a vision of the Guru. Missionary or visionary.
5. You are there to just serve and give comfort to the Guru.

You are with the Guru because you belong to the Guru. There is no choice.