In fact, sometimes she gets so friendly that it backfires and men get the wrong idea.

Carpets have the effect of a dust pocket, with merit of sucking up dust and stopping it flying around, but you can say that effect backfires.

But this support could weaken or even cease if the dollar falls too low, if the price of oil rises too high, or if the American economy backfires. In fact, the US economy has become increasingly detached from reality.