"Oh, that's crabs for you ... thick as planks, the lot of them. That's why you can keep them in a bucket without a lid. Any that tries to get out gets pulled back." [The speaker is Verity Pushpram, and she is reiterating what Pepe said to Glenda Sugarbean about the "crab bucket."]
Crab bucket, thought Glenda as they hurried towards the Night Kitchen. People from the [neighbourhood] disapproving when a girl takes the trolley bus. That's crab bucket. Practically everything my mum ever told me, that's crab bucket. ... The worst of it is, the crab that mostly keeps you down is you ...
-- page 298, Unseen Academicals by Terry Pratchett. London: Transworld Publishers. Copyright Terry and Lyn Pratchett 2009.