The phrase "very good" in Bereishit 1:31 is explained by our Rabbis as alluding also to the yetzer hara, frequently used in the sense of the 'productive urge':
Bereishit Rabbah 9:7:
Nahman said in R. Samuel's name: BEHOLD, IT WAS VERY GOOD refers to the Good Desire; AND BEHOLD, IT WAS VERY GOOD, to the Evil Desire. Can then the Evil Desire be very good? That would be extraordinary! But for the Evil Desire, however, no man would build a house, take a wife and beget children; and thus said Shlomo: "Again, I considered all labor and all excelling in work, that it is a man's rivalry with his neighbor (Kohelet 4:4). 2
2) It is the Evil Desire which in the first place inspires this rivalry which leads to great efforts.--One may triumph over his human failings by turning even them to noble purposes.