Given the large number of mammals that have gone extinct in North America and Eurasia since the last Ice Age, clearly due to our species, starting with giant sloths and mammoths and running along
running past Irish elk, I'm less than enthusiastic about the old days myself.
My type O system still cries Eat Meat, but I've got enough civilizing to want to temper some of those tendencies.

Missing those woolly mammoths, out there in the dawn light, puffing great clouds of water vapor into the cold air.