Maybe she is just thinking, "At first, I was panting for more of you, now I'm pantless for more of you." Hey you have your fantasy, I have mine. Great shot...beautiful smile and eyes. This is a good shot with or without pants.
I agree with ~cigsace...This is a very sexy portrait in that her eyes capture you first...then the pose...and THEN you notice she's actually nude, in a manner that this picture makes both subtle and blatant. I like the cleverness of that...very beautiful.
I might would have chosen different shoes for her...but the thing is, it adds to the naturalness of the shot - they seem like the trendy sort of thing the model actually would like - and it's certainly not a fatal flaw, if one at all.