This is called reaction.

One notices it now and then in oneself.

Sometimes when one has been extra good for a longer time than usual, one is suddenly attacked by a violent fit of not being good at all.

"I'll tell you what they do," said Peter; "they strap the broken man down so that he can't resist or interfere with their doctorish designs, and then someone holds his head, and someone holds his leg--the broken one, and pulls it till the bones fit in--with a crunch, mind you! Then they strap it up and--let's play at bone-setting!" "Oh, no!" said Phyllis.
But Bobbie said suddenly: "All right--LET'S! I'll be the doctor, and Phil can be the nurse.

You can be the broken boner; we can get at your legs more easily, because you don't wear petticoats." "I'll get the splints and bandages," said Peter; "you get the couch of suffering ready." The ropes that had tied up the boxes that had come from home were all in a wooden packing-case in the cellar.