Nothing.

The "glint in the eye," as you put it, is the personality. That is a product of genetic wiring and direct experiences growing up, and cobbled together by the brain to reflect out our histories.

Otherwise you have to go into the galactical justice system that gives some people a glint, but others a murderous glint. If we accept that we aren't special, and are just bog standard machines, but carrying around the most complicated structure in the universe in our heads, then we are exactly what you would expect.

As the late, great, Christopher Hitchens wrote, “That which can be asserted without evidence, can be dismissed without evidence.”