That resting bitch face though... she knew where he was gonna start "focusing" alright.
You can use this one to express disapproval : )
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As for me, I always focus on eyes ; )
By the way, while I love shallow depth of field and I use it very often in real life and in games, it can be easily overused. In many cases it's better to use smaller apertures / higher f-stop, especially when the background is interesting.
Take this as an example: wide aperture gives a nice blurred background, but in this particular case a background is actually very cool, so it's worth to keep it sharp. Besides, by using higher f-stop all elements of the subject are sharp, which, in case of people, is very important -- this way both eyes and nose are still in focus, which is impossible with a small f-stop.