It may sound strange, but some of my better portraits resulted from rather uncomfortable posing situations. I'm not sure I've decided whether or not making models squirm is an advisable technique for photographers, but I'll back up my claim by showing you a few examples.
Take this portrait for example:
I had an image in my mind of this model shyly clearing her hair from her face, but figuring out exactly how to pose her was a lot harder than I imagined. I had her moving her hand a centimeter to the left or to the right, or rotating by a measure of degrees. In fact (at the risk of ruining my portrait), the look she's giving me in this picture is probably along the lines of “Ummm... like this?” But even though the pose felt so contrived as we were standing there shooting, the portrait doesn't really show it.
I generally work with inexperienced models, and perhaps less experience means higher chance of awkwardness. But I think what I'm asking here is does more awkwardness increase the quality of a pose or expression? Well, surely there must be some threshold where the awkwardness during the shoot starts to seep right onto the film. Yet I wonder if there might be something about the pressure, the discomfort of being posed that can call out the candor and honesty required for a good portrait.
This photo felt ridiculous when I was taking it. I had dragged a couch out of the corner of our living room and set up these two kitchen chairs in its place. Poor Grandma and Grandpa didn't really know what to do, and I didn't know exactly what I wanted them to do, other than sit on the chairs. I think out of the awkwardness of the situation, Grandpa just started laughing, and that's how I got this shot.
You might be able to imagine how goofy this model felt as he growled and clenched his teeth. I think he figured the photo would look as stupid as he felt as I was pointing the camera at him. But I think it's a really unique portrait.
I was trying a somewhat advanced pose with this model, and I wasn't even sure how to execute it myself. I had her leaning and bending and twisting; but she made something interesting out of it, and I'm happy with the result.
I guess I haven't come to a concrete conclusion. I think it's important to experiment and to not shy away from poses that may feel contrived when you're shooting them; they'll likely feel a lot different as a finished portrait.