The Buddha once asked a student, “If a person is struck by an arrow, is it painful?” The student replied , “It is.” The Buddha then asked, “If the person is struck by a second arrow, is that even more painful?” The student replied again, “It is.” The Buddha then explained, “In life, we cannot always control the first arrow. However, the second arrow is our reaction to the first. And with this second arrow comes the possibility of choice.”
I read the above recently and immediately felt its truth. Staying aware of the above has helped me to see that the majority of my "suffering" is due to the second, third, fourth (and beyond) arrows, all of which are under my control.
When something bad happens, it sucks. Death is painful, being belittled hurts, but I'm able to both understand and successfully process first arrows. If something happens to me that was not under my control, I don't benefit to wish it didn't happen or pretend it hadn't — all I can do is move forward in the best way possible.
Continuing to revisit prior failures, missed opportunities, or moments of regret is, however, not helpful. The more we return to that we can't control — because it's in the past — the more we allow subsequent arrows to damage us.
The best thing we can do is notice when we start to pull an arrow from our quiver. Is something else that happened or our overall mood or energy levels causing us to want to needlessly inflict more pain to ourselves?
When we notice we might be revisiting something we don't need to, take a breath.
Come back to this moment, the only one we have control over.
Remind yourself that, as the Buddha wrote, "with this second arrow comes the possibility of choice." We don't have to beat ourselves up. We don't have to wish we had acted differently. Instead, we can choose to move forward, taking what we've learned, to live in the best way we know how.
Life will happen and arrows will come, but get rid of the extra arrows, they aren't helping, and, they aren't needed.