House rule for any ruleset. 1. A failed roll never means "nothing happens". Something changes: the situation gets worse, a cost is paid, time is lost, or a new danger appears. 2. The GM says what the failure cost before narrating it. 3. The player may always choose to succeed at a cost instead of failing, if the GM can name a fair cost. 4. Enemies who are hostile and present take their turn when a player fails near them.