Geology

Stone that's a good q, one I've long entertained. My theory is that the humanoid is after all important to He/She/It, that the slightest change in many of the constants would make our existence impossible, almost conclusive evidence.
So why don't we pursue this suggestion

It's because we think too much like the humanoid

Help Eng, Man, Oss, Con, et al, et al

Water and our atmosphere.

Right Cis, those two of the most critical. However we could spend all day citing others like gravitational constant, earth/sun size/distance, the ability of our plant life to generate O2, relative shortage of volcanoes, adequate land etc