humans and the planet are not perfect though

why dont we live as long as other animals? why are we susceptible to cancer? why is the planet full of so much useless water? i mean if you think some god designed us, why did he half ass so many factors?
i dont have any problem with humans and the earth being a mistake

i also
dont deny that there could be a creator, because there absolutely could be. all i know is that no human knows who or what it is
all i know is that i will not live my life trying to appease some magic man in the sky based off not what he told me himself, but what some human told me he wants from me