Jante Law

1: Don't think you're anything special.
2: Don't think you're as much as us.
3: Don't think you're wiser than us.
4: Don't convince yourself that you're better than us.
5: Don't think you know more than us.
6: Don't think you are more than us.
7: Don't think you are good at anything.
8: Don't laugh at us.
9: Don't think anyone cares about you.
10: Don't think you can teach us anything.
11: Don't think there's anything we don't know about you.
12: Don't even try or we'll pull you down.

Described in the 1933 novel A Fugitive Crosses His Tracks by Aksel Sandemose

Does this sound awfully and creepily familiar? A classic insight into the trollish mentality?

A.K.A. "Crab bucket Syndrome". Endemic in the UK. An excellent exposition of which is outlined in Terry Pratchett's 'Unseen Academicals'