What is Christianity?

Sounds like a stupid question doesn't it? BUT when you back up and look at it as from the outside looking in it is not so simple. 
Please be patient I am sure I will get around to offending everyone before I am through. 
Here are some examples of what I am talking about.
What is a Christian?
Do you go to heaven just by calling yourself a Christian?
Christians claim to be saved by grace but is that all there is to it?
Does grace give you the license to go out and live however you please?
Are there rules that Christians must live by?
If so then what are the rules?
I could go on but, if you had a group of people who call themselves Christians in a room and asked these questions I am sure that you would have a lively debate on your hands by now.
About eighty percent of Americans call themselves Christian and believe that they will go to heaven when they die but there are a myriad of differing thoughts on what it means to be a Christian and how a Christian should live.
So who is right?
GOD!
So we must go to His word and see what He says BUT then you have debates about which scriptures apply and which ones don't.
Now are you beginning to see that it is not such a simple question?
So now we get to the bottom line. There is so much confusion about Christianity because we pick and choose which scriptures that we want to live by and discard the ones that are inconvenient. Maybe we should go back to believing the whole Bible!
BUT then we might actually have to do something as Christians!