Portraiture can be challenging for photographers. It requires building a relationship with the subject. Something that can be uncomfortable, and completely unnecessary for other types of photography such as landscape, architecture and commercial photography.
In portraiture, there is nothing more captivating to a photographer than the eyes. They can convey so much in such little space. They say the eyes are the window to the soul; conveying emotion, telling a story, inviting you to listen without saying a word.