If I remember correctly, there is a Japanese saying that translates roughly into something like this
"Every person has three hearts, one which he shows to the world, one which he only shows to his closest of friends/family, and yet another one which is known only to himself"
Similarly In Hinduism there are many schools/flavors. It caters to the wishes of the followers..and because it has no founder or central dogmatic text, people have; over millennia come to pick and choose, and even add/modify Hinduism into schools of thought they prefer.
1 There are gods and deities(even these are considered to be but pointers to a singular god/goddess) for the masses which need something to pray to/ask boons of
2 There are philosophical schools which posit that man and god are but the same
3 and Finally there are also philosophies which posit that even gods can be transcended (similar to Buddha nature in Buddhism).
In Buddhism one finds something Similar, As a Tibetan Lama recounts
The Buddha taught three different kinds of people.
1 He taught ordinary people who just wanted to get rid of their own problems, who just wanted to live better with less problems. He taught those about cause and effect.
2 Then other people have the need for a rich inner life. They want to feel something, they want something to happen inside. They can't just be satisfied with getting out of trouble; they want something meaningful inside. And those he taught about compassion and wisdom, how to develop these qualities.
3 And finally, then, there was a group of people who weren't able to see the Buddha as a person or a man or something out there, but as a mirror to their own face, something showing their own potential. And those he taught about their own Buddha mind, their timeless Buddha nature.
Even though later generations of Buddhists (Incidentally Buddha never claimed to be starting a new religion..the term "Buddhism" was coined by his followers maybe a few generations after his death)claimed to be separate from Hinduism, for those of the philosophical schools of the Dharmic ways (Hinduism, Buddhism, Jainism) there was no real difference.
Especially Zen Buddhism, and the non-dual schools of Hindu philosophy(Advaita Vedanta) are almost identical to the T.
As an Advaita Hindu, I practice Dhyan(Meditation)...the word Dhayan, when it came to China, morphed into Chan...and later into "Zen" in Japan. Bodhidharma , known as Damo and Daruma in China/Japan was a great proponent of Dhyan.
When you look at Buddhism today, you see the major groups..the Theravadins and the mahayanists...The Mahayanists have almost become indistinguishable from the hindu philosophies which deal with gods and deities.
The Theravadins are similar to the other Hindu philosophies.
The "nothingness" Buddha speaks of and other concepts are already to be found in the philosophical texts of Hinduism which predate him, but most people do not know about them cos for them Hinduism = many gods :)
As a Hindu, I am very interested in the religious and philosophical traditions of the world. The Hopi and other native American mythologies, and the Celtic ones are fascinating to me. And I see a lot of similarities between the Shinto religious deities(kami's) and many local Hindu/Buddhist deities.
The Mayan Maize god will not look out of place in any Hindu/Buddhist temple :D
Mayan Maize God (South/Central) America
Hindu/Buddhist deity Hanuman
The Similarities are so striking!