Roughly 10 million years ago, some weird human ancestor mutated genes that expressed the alcohol dehydrogenase enzyme ADH4. Without this enzyme, alcohol couldn’t have been metabolized by the body. Our tree-clinging relatives found eating fermented fruits supplemented their diet, besides being pleasant, so those monkey-like creatures which could ingest alcohol were favored by natural selection. Today, humans can metabolize 40 times more ethanol than these first pioneers. In other words, it took a lot of training over many generations to get to where we are today.
Was it worth it?