Weird, I find height much easier to remember in the metric system - everyone's a meter something (unless you're a kid, or as tall as Glenn Jacobs), like "meter sixty five", so you just remember the last two numbers. With feet and inches you have as much cognitive information ("five foot five"), or more because the number of inches is base 12 instead of base 10, but almost 1/3rd the accuracy!
And doing relative calculations (ex "10% longer than 5'11") requires extra steps (1.1 * (5 * 12 + 11), and then convert to feet and inches again), while with metric anyone can do it in his head on the fly! Even typing "5 ft 11 in" into Google is a pain in the ass compared to "180 cm", and I still can't figure out how to get it to produce output in both feet and inches!