The Anti-Mob Mentality

Why does the "mob mentality" only kick in when it's something bad?  If you drop to the ground from a heart attack, the more people there are around you the less likely it is you'll be helped.  Conversely, if there's a large crowd of people, the more likely it is a bad situation will get worse.

Maybe there should be posi-mobs walking around. They could yell things like "Tell someone you love them!" or "Take a minute to appreciate nature!"

 They could be just as loud and obnoxious as the mobs that develop for negative ideas - they'd just be using peer pressure for happier reasons.