Cf: A bow long bent at last waxes weak (Br.). A bow too much bent will break (Am.). Even a worm will turn (Am., Br.). A man may bear till his back break (Br.). A man may provoke his own dog to bite him (Am., Br.). Patience is a stout horse, but it will tire at last (Br.). Rub a galled horse and he will kick (Am.). There's a limit to everything (Am., Br.). Tramp on a snail, and she'll shoot out her horns (Br.). Tread on a worm and it will turn (Am., Br.). Tread on a worm's tail and it will turn (Br.). When the well is full, it will run over (Br.). The worm will turn (Am.)
Русско-английский словарь пословиц и поговорок. Академик.ру. 2013.