example - take 100 people, measure how tall they are, take the average, call the average "normal". It is unlikely that anyone of the 100 people will have the exact average height. 50% will be taller, and thus too tall to be normal, 50% will be shorter, thus to short to be normal.
I can do normal - I do it most of every day. It only starts to slip if people start prying with respect to my personal philosophy, political views, sexual history, hobbies or life experience. Although when you get into such things, just about everybody's normal slips.