Why does Jesus need Christian's to prove to me that he is real? Isn't he real enough to make his existence known to me? He knows exactly what evidence I need to know he's real, so using his underlings who don't know what evidence I require is a poor decision.
The reality of Jesus is a matter of historical fact. He lived, was crucified and died, and then three days later appeared alive to his disciples. Again, this is a matter of historical record. Now, you may not want to accept the record, but that doesn't somehow negate that it exists.
Why should Jesus give you any more evidence than already exists to persuade you of the reality of his existence? Why should he jump through your particular set of evidentiary hoops to convince you he is real? There is evidence enough. You may reject it if you like, but you are the only one who will pay a price for doing so. God is not diminished one iota by your refusal to believe in Him.
Since every Christian I've met has very different idea's about God, and that they construct different theories about Gods existence, I'm left in continual doubt. I need more that a mixed bag of ideas here, I need something concrete, but this God of yours has never given me concrete evidence of his existence.
I've lived among Christians all my life. I haven't encountered this "mixed bag" you're talking about when it comes to God. In my experience, there is a near-universally held set of ideas about God among Christians: omnipotence, omniscience, omnipresence, timelessness, necessarily existent, the uncaused First Cause, etc. In any case, the best revelation of God you can find is in the Bible. If you want to know who God is, read it.
Which makes me think, what kind of evidence did you receive from Jesus himself that was concrete enough to base your whole life around Christianity?
In terms of personal experience, I have the work of God's Spirit, called the spirit of Christ in the Bible, that assures me of the reality of my relationship with God and the truth of His word. God's Spirit convicts me of sin, illuminates my mind to divine truth, comforts me in troubled times, strengthens me in the midst of temptation and weakness - all as the Bible says He will.
There are other reasons, more academic and philosophical reasons, for my faith, but my direct experience of God in my life gives me the same certainty about God that my daily experience of my wife gives me about her.