I think I'm meant to be funny and charming here... but I don't like to do such things on demand. Whenever the expectation is that I go left, I really really really feel like going right.
Plus I'm just extremely disinclined to faking things, pretending to be something I'm not. My lack of smiling photos is an example of that; I don't feel happy when I take a photo, I feel neutral - so why the fuck would I smile? Such is my apparently alien way of thinking :P.
I made an exception for making a sarcastic expression photo though, because that just amuses me. Especially the different ways people interpret it... interesting stuff ;).