Make it a rule in life never to regret and never look back. Regret is an appalling waste of energy; you can't build on it; it is good only for wallowing in.
That Katherine Mansfield quote is essentially an eloquent way of saying your favorite tattoo phrase and mine, "No regrets."
And I couldn't disagree with it more if I tried.
When I first told Jane about my aversion to the concept of "no regrets," she told me that she, herself, is a no-regrets kind of person. She explained that she doesn't want to look back and sigh over having not done something; kind of a FOMO conception of regret (though she didn't say FOMO and I don't think she ever would).
But that's not the kind of "no regrets" attitude I'm talking about. I'm talking about people who make mistakes and shrug them off with no remorse or sorrow, driven to live a life they insist on perceiving as perfect.
It may seem like a cool DGAF lifestyle, but there's nothing more terrifying to me than someone who claims to have no regrets over anything they've done. Logically speaking, that indicates a very low ethical threshold for future behavior. If they automatically forgive themselves—or don't even see a reason forgiveness is necessary—for their transgressions against others, why wouldn't they hurt you, too? It's not like it's going to haunt their conscience for the rest of their lives or anything. YOLO!
To insist on looking back at things you've done with "no regrets" is to disregard the emotions of anyone you've ever hurt, and to deny your own natural emotions. If you have any. "No regrets" is kind of sociopathic, when you think about it.
I see regret as normal and necessary and even useful. It's the humble act of accepting responsibility when you've made a mistake. And that uncomfortable fizz in your gut that you feel when you think about that mistake serves to stop you from making similar mistakes in the future.
Regret is also understandably wishing things went differently, even when you're not to blame. I regret driving eight hours to Tallahassee to see a guy that assaulted me when I got there. It's not my fault that he hurt me, but he wouldn't have had the chance if I hadn't made that drive.
Regret teaches. Regret heightens your empathy and expands your compassion. It sharpens your vigilance. Regret simultaneously softens and hardens.
Of course, there's the argument that everything you've done—mistakes included—have made you who you are. But regretting some of the decisions you've made doesn't mean you are somehow less accepting of yourself; it's merely being aware that you haven't been perfect. Why do you have to go to your grave thinking, "Yep, I did everything right"? That's a hell of a lot of pressure.
I don't believe in dwelling on regret, of course. Beating yourself up, at length and repeatedly, over the past can be emotionally debilitating. So in that way, I agree with Mansfield—you shouldn't wallow.
But I'll conclude with a quote from a Katherine I completely agree with. A Katharine, actually. Katharine Hepburn.
I have many regrets, and I'm sure everyone does. The stupid things you do, you regret if you have any sense, and if you don't regret them, maybe you're stupid.