Use 'backfire' to describe a plan's outcome as the opposite of what was intended. Trying to cut the pie evenly backfired, leaving everyone with tiny slices.
Pro Tip 2/3
Irony or Surprise
Often involves an element of irony or surprise when the result is less favorable than expected. His efforts to impress the interviewers backfired, causing embarrassment.
Pro Tip 3/3
Negative Consequences
Emphasizes that actions can have negative consequences, not merely different outcomes. The aggressive marketing campaign backfired, turning customers away.