"How are you?" "Good"

So, a normal conversation usually starts with "How are you?" and then the other person says "Good, how are you?". I was on the phone the other day, and the person I was talking to asked me how I was, and I automatically said "Good, how are you?". When the other person responded, they started to say "good", but quickly took it back and confessed to me that she wasn't good. It made me think, how many times to do we robotically respond with a "good" when we are so far from good. I know that I have done this many many times. Now, I understand that you're not going to spill everything that's going on in your head to a random stranger that asks you how you're doing, but what about your close friends? Don't they deserve to know what's really going on? I feel like such a hypocrite right now because that it something I completely fail to do--tell my friends what's really going on. I have failed miserably when it comes to that. I feel like I have trained myself to alway say "good" when somebody asks me how I'm doing. 


Opening up is something that I struggle with tremendously. If someone is asking me question about how I'm doing specifically I do everything to avoid answering those questions, and if I have to I'll just drop the one-word answers like good, okay, fine, nothing etc. I just wish I could always answer honestly to how I'm doing. But the truth is, doing that scares me! It scares me a lot! The last thing I want if for someone to know what is going on in my head. And I feel like once I open the door, there is no way I'll be able to close it and I don't want that. 
I guess I'm just going to have find a happy medium. I need to choose my words wisely and always answer honestly.