When I'm writing in my diary, I often don't know if I should write 'Dear God' or 'Dear Diary'.
I mean, does it really influence the way I write? Would I tell my "Diary" things I wouldn't tell God? No, I don't think that's the problem -- at least, not with me.
God knows everything, right? So, when I write "Dear God" I think, what's the point of writing about my day, what's been happening in my life -- if God already knows about it?
In Genesis, when Adam and Eve have sinned, and eaten an apple from the tree that God has told them not to eat from, it says that God is taking a walk in the garden, and he calls to Adam, "Where are you?". I know it's only three words, but if God knows everything, then he knows where Adam is, right? But he wanted to hear it from Adam, just like he wants to hear everything from us.
I mean, say you got a detention at school, for showing disrespect to a teacher. While your at school, your parents might get a call from the principal, or something. But when you get home, they won't automatically say, "Hey you, stop right where you are -- you got a detention today." and demand to know what it was about.
No, most likely they'll ask how was school was, and if you don't tell them about the dentention then, they'll say something like, " Mmm. Anything you're not telling me?"
They already know all about it, but they like to hear it from you. What you're thinking, what you thought the whole thing was about, what it meant to you. God is the same. He loves hearing what we have to say.
Don't keep your life from God, with the excuse that He already knows.