You know, being all black and all, it took me a while to understand he was facepalming with his eyes closed. And by the way, for being aliens, they have amazingly human gestures, expressions, and reactions. Then again, if they didn't, it would be pretty hard for us to follow the story comfortably, wouldn't it? And now that I think about it, animals more or less express fear, anger, delight etc. with expressions similar to humans'. And the aliens in Mass Effect that are incapable of expressions and as such express their feelings in words whenever they say something are a bit annoying to talk with.