Hydrogen and oxygen are volatile agents of combustion, but the same are the only ingredients of water which douses combustion. The designer/creator of these must've had a chuckle, thinking about folks like you when he designed it all so mindbogglingly inexplicable.
That's not very "inexplicable" if you've read a little chemistry - water is merely the "ash" of burning hydrogen. You don't expect wood ashes to burn, do you?
And when it comes to complexity, DNA isn't all that snazzy. The individual nucleotides are middling-fancy molecules, all right, but there are only four of them in long, monotonous chains. Not even remotely as complex as the proteins they code for.