True.
But the point is that it must have all 3 main factors to be considered "Bullying."
Teasing can hurt someones feelings, sure.
Example: One person, even a primary person in someones life, saying, "You are ugly' does not have the same lasting effects on a person as it does for someone hearing those things every day for five years... (But it still sucks!)
Bullying is about patterns, and intensity, and prolonged exposure.
Hurt feelings are not the same thing - and, yes, hurt feelings can also have lasting effects on a person, but hurt feelings, based on one incident, or even three for that matter, are not scientifically considered 'the same' as psychological and emotional harm due to long term abuse.
Teasing is different than bullying.