Found this amusing quote somewhere  :
"I personally like to drill holes in my socks to save weight. I estimate you can drill out approximately 50% of the sock without compromising structural integrity. And the actual performance benefit is much greater than the dry weight reduction due to the reduction in rotational inertia through your pedal stroke"
. . . but then drilling holes in chainwheels, brake levers etc used to be the vogue ... and of course minimising the length of the bit of cable that protrudes from the brake caliper!