hifi_civic

im building a b16 head right now. i got it milled and port and polished. i was looking around for valves, springs, and retainers. i just bought skunk2 high compression/ stock size valves, dual valve springs, and titanium retainers. one of my friends told me i gotta lap the valves into the head. by this time i was pretty mad cuz i just put in all my valves and **** in by hand and it took like 4 hours. what exactly is valve lapping, is it absolutely necessary. since i have a brand new head and brand new valves, do i still have to. just checking with you guys before i take it all off again. let me know. asap. thanks
rob