Aren't we all agnostic?

We can say we believe there is a god, but we cannot say there is a god, because there is no proof of that. Besides, if God or any god exists why can't they be forthright and say: "Look buddy, here I am". If I knock on your door while you are at home and nobody answers will you believe that I was there if I phone you the next day and ask you why you didn't answer the door. No and why should you. It’s the same with God, I have knocked on his door, but there was no response. Is there any reason why the gods have to behave mysteriously? I can come up with one reason: They feel ashamed of themselves for having made so many mistakes and letting us down, time and time again