I used to throw one in every now and then. I once felt it appropriately symbolised my feeling at the time. But now, my boss has killed it for me. In mass emails, notes, on the sign in board for sobbing out loud. It's too much. Just. Too. Much. I'm finding now it's having a reverse smiley effect on me - now when I see one, I want to vomit, and when faced with a situation where I might've ordinarily used one, I quietly shudder.
I feel that smiley face over-use is definitely a punishable offence. Jail time even.