Social Proof

Social proof is the mental shortcut based on the assumption that, if everyone is doing it, it must be right.

This is like pretty similar to Mob Mentality.

“New York Times Best Seller”

Social proof is so common that it easily passes unnoticed.

While few people really like to wait in long lines, we might do it anyway in certain situations. If enough people are willing to wait it (usually) is a sign that there is something worth having at the end. A line in front of a restaurant, movie, etc. is social proof that will likely influence other people to try.