I will try to answer as honestly as I can.
For me, the notion that "there was a singularity" and "something exploded" causing the universe to spring into being, that universe being "infinite" or "all that exists" makes no sense at all. That "infinite" universe, I am asked to believe, is still expanding...but nobody seems to know just how "all there is" could be expanding...what, exactly, is it expanding into?
It seems more reasonable to me to suppose that the Universe did have an "Intelligent Designer". But what sort of Intelligent Designer?
Of course, I had a predilection toward Christianity, since it was what I grew up with, but my family weren't really terribly religious, and I grew up in the sixties, when a generation was searching for it's own spirituality, and religion was everywhere. (Today's "Pagans" and "Wiccans" etc. are the children of the Hippie era.) Being a very curious being, I took out reams of books about religion and spirituality, and devoured them. I also sampled several different methods of worship for myself. (I am still grateful for having learned Yoga during that time. I recommend it for any young woman contemplating having children.)
Anyway, it didn't seem logical to suppose that the universe actually needed more than One Creator. Nor does it seem as if any Entity powerful enough to create a universe from scratch, and then people it with life would be difficult for the human mind to understand. It does seem logical, however, to suppose that He would wish to have communication with His creation.
Then, too, there are all those similar "myths" and "legends"...we all know them. The creation story, the flood story, a being that brings forbidden knowledge from heaven, etc, etc...and how many dying but ever-living saviors are there? Don't almost all of them meet certian criteria...like the virgin birth, born in mid winter, born in a cave, rejected, etc, etc... No, coincidence just can't explain all that, not when you consider that the people who held these beliefs were separated by both time and distance. The explanation that they were primitive people who made up their gods to explain things like lightning and to ease the fear of death don't hold up under close examination, either. None of those oh-so-glib explanations really made sense to me...not then, and not now.
Once you accept that God exists, and that the legends are true, it is time to decide which God. We've eliminated a few, but there are many left.
Does history tell us anything? A little, maybe, but not really enough. Well, what about archeology? Better. Archeologists have uncovered places that the Bible speaks about...could the Bible be true? Well, alot of the history it tells obviously happened. The God the Bible speaks of fits the rest of our criteria...could this be the Creator? This seems to be the best representation of Him I could find. OK, it's not perfect...but remember, a good bit of it was written during some very primitive times.
Jesus, however, is far from barbaric. He has great power, but He never uses it to serve Himself. He feeds thousands of people, but He never takes food from anyone. He heals countless numbers of people, but you never hear of Him harming anyone. He raises from the dead, but He never kills anyone. He never even defends Himself, not even when He is facing His killers.
Then there was my tenth grade Biology teacher. I had such a CRUSH on him, he was HOT!! He taught us that energy could not be created, nor could it be destroyed...it could only change form. That hit me, really hard. But...energy had to come from somewhere, didn't it?
God, of course, is the ultimate Source of Energy. Isn't life energy?
I am a Christian.