rock the boat


Disturb a stable situation, as in An easygoing manager, he won't rock the boat unless it's absolutely necessary. This idiom alludes to capsizing a small vessel, such as a canoe, by moving about in it too violently. [Colloquial; early 1900s]

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.