Upset The Applecart Meaning

(idiomatic) To disorganize or spoil something, especially an established arrangement or plan.

Example: 1900, E. Phillips Oppenheim, A Millionaire of Yesterday. ch. 22:
  "But why go near him at all? He thinks that you are dead. He has no idea that you are in England. Why should he know? Why do you risk ruin like this?"
  "There are three reasons," Trent answered. "First, he may find his way to England and upset the applecart . . ."
1922, William Somerset Maugham, Caesar's Wife, act 3:
  She told me herself just now that the worst was over. And those confounded people must go and upset the applecart.
1979 Dec. 10, "Business: Putting Brakes on a Bailout," Time:
  Last week the Senate Banking Committee upset the carefully stacked apple cart when it voted 10 to 5 not to approve the Administration's bill.
2011, Mira Bartók, The Memory Palace, ISBN 9781439183311, p. 5 (Google preview):
  This kind of impact causes contusions in the front and back areas of the brain and can create microscopic bleeding and shearing of neural pathways, causing synapses to misfire, upsetting the applecart of your brain, sometimes forever.