I don't mind stickers at all. I've been sending my wife various stickers this evening from Mario to Weather Channel. lol I don't see the big hate towards it. To me it just adds some fun to otherwise plain messages.
I thought they were dumb and sent them to my wife just to bug her. Only they didn't bug her. And as much as I hate to admit it I'm starting to think they're kind of fun. I will never spend a dime on them though. Only ones I've downloaded so far are Dunkin Donuts and Yelp.