The story of Noah's ark was one of many that stood out to me, even as a young child, as implausible. But while most of the other children at Sunday School were focused on the logistical details about the number animals that could fit on a boat and the implications of having so many species sharing such a small space, my thoughts were elsewhere. I figured that fitting so many different animals on board could be a miracle, and I was willing to let that slide. I was far more interested in the source of the massive genocidal flood that made Noah's ark necessary.
The adults around me seemed to expect me to believe in a god that loved us despite it having rid the planet of virtually all humans previously. And why did it send the great flood that made the ark necessary? The humans at the time had upset it. They had exercised the "free will" we hear so much about and were subsequently exterminated by a "loving god." This was the main problem I had with the Noah story. The kind of god that would do this was anything but loving; it was a monster.
If a man came home from work one night and murdered his entire family because they had disappointed him, how many of us would regard him as loving? Would it matter that he had previously given them a list of demands so that they knew what he wanted? Of course not! We'd be appalled by his actions, and I don't think the idea that we should worship him is one that would occur to most of us.
The Old Testament depicts this god engaging in the most extreme acts of cruelty humans at the time could imagine. Some, like genocide, have stood the test of time in the sense that they still rank at or near the top of the worst we can imagine today. Stories like that of Noah, combined with the many tales in which this god compelled humans to act against its will (all the stuff about it "hardening hearts") and then brutally punished them for doing so, effectively demolishes the idea that evil is necessary because of free will. Instead, we see a jealous and murderous god who treats humans in much the same way a puppy treats a chew toy.
Sure, Christians want us to believe that everything changed in the New Testament. But wouldn't that mean that the god of the Old Testament was wrong? How much sense does it make for a being like this to change its mind? Assuming that the primary god described in the Old Testament (because there were other gods mentioned) is the same one described in the New Testament, it seems like we still have some serious problems regarding it as anything other than a monster.
It would almost make more sense if Christians openly worshipped this monster-god out of fear. Fear of such a being would certainly be an appropriate response to much of what their "holy" book says. If one believed in a god this cruel, it seems reasonable that one would fear such a being and seek to appease it. And yet, even the "god-fearing" Christians seek to convince us that their god is loving. It seems like stories like that of Noah offer vivid counterexamples.
