We all need a god; there's just something inside of us that makes us want to have someone or something guiding us.
Partly, I think this is because gods give us purpose. Having gods gives are lives meaning and definition.
So, have we invented a god? Have Christians invented a god that matches our ideals, our values, our beliefs? It's a claim I've heard often from many Atheists: Christians simply have invented a god because we - as humans - have this desire to have god(s). And it makes sense for the most part. While others cling onto things such as money, popularity, and significant others, Christians have invented a god of their own to fill this gap.
I would never deny that we need a god. I would never deny that YHWH (the Christian - and Jewish God) fills this whole in our lives. However, I'm not so sure that the Christian God is an ideal one in the human mind to fill the gap of a god.
One thing we must remember about gods is that we want them on our terms. With regard to money, we see it as something we deserve (by virtue of our labor or inheritance). These are terms bestowed on this god by us. This is why money is such a popular god - because we feel we can control it, or at least set it's level of power in our lives. And this is also the reason we have so many problems when we make things our gods that depend on others. Making a lover our god is not possible on our terms alone, neither is popularity. We must depend on the terms of others as well in these situations. This is why these gods never work out.
Because our inclination is to desire gods on our terms, the Christian god is not an ideal one. YHWH demands worship from his servants, in good times and bad. Jesus demands us to be merciful and peacemakers. These are not our terms, these are His. And this is why so many of us Christians are not the people He has called us to be - because we are still demanding we make YHWH god on our terms. The Christian God is not a god that ideally fits our values or beliefs either. This is why the Sermon on the Mount is so bizzare; it runs counter to things even our 'good nature' tells us to do. And this is why Jesus was executed. He does not fit our ideals, but instead commands us to conform to His.
But more importantly, just because YHWH can fill the need for a god in our lives, does it make him one of our own inventing? No, I don't believe so. If I were to invent a god, I certainly wouldn't invent someone who demands complete control over my life. Just because we fill our lives with a God (YHWH), it doesn't negate his reality. True, we do have an innate desire to worship something. But that doesn't mean that what we worship must be of our design, although for many people it is.
A god is necessary for us to live as humans. It's natural, it's innate. Our lives would feel incomplete without worship. So, we worship the sand castles we make with our hands. But it is still never enough. Because we can only experience TRUE worship, when we have a TRUE God. And only then do we find that the necessity of a god is a real one, that can actually be filled by a real GOD.