I think the main problem causing us doubts about the existence of God is the fact that for the most part, we cant see him, hear him or touch him. We cant verify his existence the way we can verify the existence of most other things. It is like standing in a dark room...we cant see if there is someone there or not.
Yet there are many things we take by faith though we cant really confirm with our senses. Like how do we know what we are experiencing in our wake time is real and what we experienced in our dreams is not? How do we know that everything we see and hear and touch isnt a dream? Like in the Matrix. How do we know the neurons or whatever that connect our eyes to our brain accurately transmits the correct info such that what we think we see is actually there? Frankly we dont. We just have to take it by faith in reality itself. So faith isn't such a bad word after all cos most of life is lived this way.