How can you believe in God when you can't see him?

Do you believe in the wind? Yet you have never seen it.

All you have seen is its effects and sometimes the wind on your face.

Likewise when you see a tree blown over then you must think that the wind blew it down because there was a storm last night.

Likewise if you look at the way the earth is made for man to thrive and prosper on this earth. You must consider that something made all these things that we use. Food, shelter and other things this is all created by God/Allah.

So when someone does something for you its polite to say thank you, right?

What about the one who created everything for you, why don't you thank him? why don't you thank God/Allah.