Well if we can’t trust emoticons to express how we feel, who can we trust?
A study published in Current Biology reveals that Easterners and Westerners use different facial cues to recognize emotion. While we scan all features, Asians tend to focus on the eyes, which can lead to cultural confusion, particularly when interpreting emotions like fear, surprise, disgust and anger. (NB if you ever see me, best to assume I’m displaying all four.)
Interestingly, this accounts for why Asians often opt for different emoticons than we do. Here, the mouth tends to do the heavy lifting, whereas in the East there are myriad variations in the eyes. To wit:
Western Happy : )
Eastern Happy ^_^
Western Sad : (
Eastern Sad ;_; (tears! so clever!)
Western Surprised :0
Eastern Surprised O_o
You get the picture. Now this is the part where I make an unseemly joke about their eyes never actually being open wide. What’s the agreed-upon emoticon for Don’t Hit Me?
No Happy Medium 
I’ve wondered why some people choose one or the other emoticon, and theorized it might be a masculine versus feminine thing. I hadn’t thought of East versus West. Looking at your examples, I think another thing that might factor in is the difference between Eastern, vertically oriented, versus Western, horizontally oriented, writing styles, although I know they aren’t mutually exclusive.
Yes. It didn’t even occur to me that the orientation was the reason, but the vertical vs horizontal style is, indeed, a distinguishing feature.