Do Christians decide if God is real?

A while back, I wrote about whether it is appropriate for Christians put reason above God's Word when it
comes to belief in Christ. You might think I'm repeating myself, here. I assure you, this is a different thing. The other post had to do with prioritizing reason above God's revelation. This one has to do with our role in belief.

In other words, while the previous post discussed whether or not reason should be prioritized over God's Word when it comes to understanding what is true and what is not, today I want to look at whether God's existence is dependent on our own personal beliefs about Him. It is an important distinction to make and hopefully it is one which can be understood properly. It essentially comes down to the question, "Do we create God by believing in Him?"

Can God be both Just and Merciful?

Is God a God of justice? Or is He a God of mercy? Are those two things mutually exclusive? It seems that whichever direction we go with this, God is accused of doing wrong.

Many have claimed that the God of the Old Testament was mean, capricious, vindictive, petty, unjust and much, much more. This usually stems from passages having to do with the flood, the destruction of Sodom and Gomorrah, the cleansing of the Promised Land of other nations and tribes, etc.

People will refer to these parts of the Bible and claim that God is a horrible, mean, violent deity. So much so that some people will claim that, even if they were convinced that this God exists, they would not follow such a being. They simply don't like Him. They don't believe such a God exists, but hate Him anyway.