Good god that's a serious nay. Do that in your own home not at the office (unless you have a private office where I can't see it). Personal hygiene should be taken care of before coming to work.
My problem is when people cut their nails in the office let them fly all over the place without cleaning them up. That's the image that came to mind in the parent's comment and it grossed me out.
Essentially, if whatever you're doing involves leaving visible bits of you behind (e.g. nail cutting) please do it at home or in the bathroom at work.