Why is God so complex. I'm catholic, and to what i'm told He is spiritual and both a human at the same time. He spoke in parables that many didn't understand, too.

Why is it that He is so difficult to grasp? Basically, what i'm asking is, wouldn't more people believe in Him, if they didn't have so many unanswered questions about his existence? I know this is where faith comes in, but still.