Place it just after the failed attempt in your edit, then follow it with the sad violin to close the moment. If the mistake is a wrong choice, put the wrong answer sound before it so the reaction answers the error.
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This 16-second Portuguese reaction clip is built around the line that things are not being easy, credited to Raider. It gives a tired, frustrated feeling, like facing a task that keeps getting harder instead of simpler. That plain, worn-down mood is what makes it easy to recognise and reuse when a plan is falling apart.