know which side of one's bread is buttered

know which side of (one's) bread is buttered

To know how to best ensure one's success. I know which side of my bread is buttered, so I was very nice to the recruiter and promptly sent her a thank you card after our interview.
See also: bread, butter, know, of, side
Farlex Dictionary of Idioms.

know which side of one's bread is buttered

Be aware of where one's best interests lie, as in Jerry always helps out his boss; he knows which side of his bread is buttered. This expression alludes to the more favorable, or buttered, side of bread and has been used metaphorically since the early 1500s.
See also: bread, butter, know, of, side
The American Heritage® Dictionary of Idioms by Christine Ammer.
See also:
  • know on which side your bread is buttered
  • know which side (one's) bread is buttered (on)
  • as we know it
  • I know
  • before you know where you are
  • by any chance
  • AFAIK
  • a closed book
  • closed book, a
  • before you know it