Lots of roleplaying games have systems for blunders or botches where you don't just fail to succeed, you actually make things worse. In Asylum we call these accidental effects Consequences, and they've gone through several stages of evolution during our playtest.
The first draft for Asylum had consequences popping up on the natural roll of "1." That mechanic didn't even each reach the playtest stage because I understood that with a d10, consequences would be happening on 10% of turns. If you know something about statistics then you probably understand just how frequent consequences become when most scenes are made up of about a dozen dice rolls. (Roughly 72% of such scenes would have consequences!) If we'd actually moved ahead with rolls of "1" triggering consequences, then either the severity of consequences would have to have to be minimal or our scene and challenge system would be too unpredictable for Narrators to use.
We ended up first testing a simple "If you miss by five or more" consequence trigger. This actually had issues in that when a character was acting with skills they were proficient in, it was almost impossible for them to trigger a consequence. However, for character that were acting outside of their competency, consequences popped up 20-30% of the time! Because the Asylum system is very transparent and easy to use, playtesters instinctively eliminated almost all possibility for consequence by working together and focusing on their character's core competencies. That may sound like "working as intended", but we actually saw this as problematic. Basically, consequences eliminated any incentive to ever act outside of a character's specialization. One of our main design goals for Asylum is balance for the sake of participation. Part of that concept, for us, is that players and characters should feel as though anything they do has the potential to make a clear impact on the scene.
Our final implementation for consequences actually helped deal with our problem with the specialty die as well. Instead of letting pure chance determine when consequences occur, Asylum instead introduces them as an agreement between the Narrator and the players. The Narrator may at any time offer the player to "risk" themselves on a course of action. The Narrator may also designate an action as "risky." To incentivize this taking said risk, the Narrator offers a Specialty die which can significantly improve the outcome of the action by ensuring a higher roll and more Impact. However, if either die results in a "natural 1" then a consequence is triggered!
The advantage of this type of trigger is that consequences only get introduced when the Narrators and players are prepared and interested in interjecting. What's more, cautious players can attempt to limit consequences by avoiding actions that the Narrator designates as risky. As someone who has been narrating Asylum quite a bit, I love using risks to simultaneously hint at danger and tempt players into bold actions.