Here's where it comes down to whether you can believe in something.
I know God is real and THE God because I know him personally. I talk to Him every day. He works in my life in ways that no one else could, preparing me for things that have happened in ways that no one else could. I have seen Him heal people in ways that have flabbergasted doctors, just because those people prayed in faith to be healed.
To answer the questions why humans, what does God look like, etc:
Genesis 1:27-28
27) So God created man in his own image, in the image of God created he him; male and female created he them.
28) And God blessed them, and God said unto them, Be fruitful, and multiply, and replenish the earth, and subdue it: and have dominion over the fish of the sea, and over the fowl of the air, and over every living thing that moveth upon the earth.
But the Bible tells us that the form God has is not a physical form, but a spiritual one:
John 4:24
24) God is a Spirit: and they that worship him must worship him in spirit and in truth.
In answer to your question about teaching love, I don't believe people in general would hold to the idea of loving their neighbor if we hadn't been taught it by God in the first place. Many people STILL don't. This is why our nations are being consumed by the greed of their leaders and businessmen.