My dad (the one wearing the pocket protector) was a design engineer who developed prototypes for GM back in the day. Being an engineer he liked to break things down into nice tidy aphorisms that made things black & white. My favorite is one he used often.
It's simple but highly effective.
Whenever I have a decision I feel confused about or that am going back and forth on I invoke it. It helps me move past the "sunk cost" rationalizations or anything else that might confuse me as to whether it was a good decision or not. Here's the secret.
Good decisions get better.
Bad decisions get worse.