By default, every goal will reset after derailing with 7 free days of safety buffer. This gives you a week off where you don't have to make progress. If you've decided the goal is too ambitious or you just don't want to do it anymore, you can also use those 7 days to archive the goal.
If you don't want that much leniency and would rather get right back to work, you can reduce the Days of mercy (in the Derail Behavior goal setting) to reduce the extra buffer week.
We say "no-mercy" but the minimum amount of mercy is 2 buffer days before you need to start working again, so there's still some mercy. If you really want to get going again and have zero safety buffer after derailing, you can contact support and we'll put you right back on an emergency day.