Admittedly, I've used the old cliche of a person staring at his or her hand while undergoing a TF. Realistically the person would probably spend 5 seconds looking at their hand, and then:

a) run to a mirror and scream;
b) run into someone else and scream;
c) run around and scream;
d) take off their clothes and look at their entire body and scream;
e) get their brain transformed first, and make a bunch of squawking or hooting noises;
f) hide from everyone and stay as quiet as possible.