Need for a face

I’ve made few acquaintances over internet over the years. They are friends through discussion forums, alumnus of my institutions, people I regularly read blogs of, or just people I’ve had email or chat conversation without meeting. All I know about them is a chat handle, an email address, a profile link or so on. In some cases I know real names and other personal or professional details. In most cases I don’t know how they look. It doesn’t matter to start with but as friendship or acquaintanceship (which may be one way in case of blog reading) grows, it starts mattering. I don’t know why but knowing a person without knowing how he looks starts becoming an itch. I think it happens with others, or not, but I tend to form an image in my mind about people how they look based on whatever I know about them, which may not be related to looks at all. I think this is because of human tendency to put a face to whom exactly they are conversing with. My imaginations are, of course, always for a shock when I happened to see real picture. But that feeling of uneasiness when I know someone reasonably well but don’t know his face is regular. Does it happen to you?