Shifteh or Shifty is a popular (f)emote used to display mischevious. The strange look on the (f)emotes' face has made this a widespread joke, many users such as Mike132 are big fans of it and use many of these.
Vladimir_Tod (AKA Vlad) was known for using excessively using the shifty emote during his time at the ACC (I think he was permabanned with the golden banhammer).
His reason for using the shifty emote a lot is because the shifty emote is perfect for any given situation.
It is a proven fact and many people developed shiftyitis from this.
There is no cure for shiftyitis.