There's always something extremely calming about photorealism, especially if you're working off a reference. Increase the difficulty level by forgetting to bring an eraser and a pencil sharpener and it becomes a bit of a race against time. Inevitably, the 'first draft' version of pencil sketches always seems to look terrible but layering is what it's all about. It's funny how the likeness to the actual person comes and goes like those 3D puzzles...there are sections that look similar and then...parts that are just a little off.
My favourite Korea's Next Top Model contestants, Dane Dehaan in his Kill Your Darlings incarnation and that one photo of Margaret Zhang that was so lovely that I had to try and draw it. If I'm staring at you in public, forget kidnappings or robbery - it's probably because you have a very drawable or photographable face and I don't think anyone has quite figured out a socially non-awkward way to say that as a compliment (yet?).