(condensed from Ein Ayah, Berachot 6:67)

Gemara: All green vegetables take away one’s good complexion. Everything that is not fully grown makes one small.

Ein Ayah: It is proper to love nature as is, for it is the work of Hashem, and to not always occupy himself with artificial things. While this is true regarding both one’s physical and spiritual lifestyles, one should be aware of the following two things.

One is that if there is something natural that was made in order to join together with something man-made, then one should not suffice with its natural completion. Since man’s intellect is also a part in the natural world, the object’s “point of completion” is actually when man is finished with it. Thus, a raw vegetable may very well not be complete until man completes it through cooking, which is also a natural action.

Another observation is that there are things that do not need human intervention, and there is a need for them to reach their completion. If man takes such an object when it is still small and not ready, it will never reach its completion.

In general, we can say that man sometimes has desires that seem natural, but the problem is that he is not ready to wait until they are at their correct stage, when they will give the full benefit. Taking them before the time will just leave man himself small and incomplete.