I get asked this question all the time by potential newbies, spectators, full-scale pilots, etc.
So as to not scare off any "customers" I say it requires hand and eye coordination and a considerable amount of control of up,down,left, right awareness w/o getting too technical. I try to mention the price last just like any good "used car saleman" would do. Should I add something else slyly or just be blunt......