I would have to say that my poor dietary decisions in my early 20's to late 30's have become my bete noir. I am now facing liver disease related to fatty liver, and my blood sugar is precariously managed. Side effects of things getting out of control include having parted ways with my gall bladder and having to have minor surgery on my knees. The knees are still original equipment but they have been tweaked a bit. There are also possible vision effects from that choice though THEY are under control as well.
There were a couple of decisions in college regarding eligible young women and dating, but I eventually DID find a good partner so that is more of a "road not traveled" case. It bothers me a lot less. Some of the decisions included being unable to get too close to women who smoked, and wrestling with the decision of telling them (and thus pressuring them to change if they wanted to be with me) or simply letting the relationship slide. I was more than slightly naive at the time.
Financially, I didn't do terribly. I'm not filthy rich but I'm comfortable in retirement.
Emotionally, the biggest decision I ever made, and it looms over all other decisions, was to refuse relocation when my employer got bought out and my division was moved to Baltimore. Instead, I chose to stay in New Orleans to personally oversee my mother's care in a nursing home where she was deep into the maze that is Alzheimer's Disease. I turned down a promotion and a separate HUGE job offer, both of which would have prevented me from managing Mom's affairs closely. And I'm glad I did because I was able to "gig" the nursing facility with regard to Mom's bedsores, keep her supplied with clothing when needed, and make some of the emergency decisions that had to be made at the time. I can still look at myself in the mirror and not hate what I did for family. It may have led to me having less money than I might have, but I did what was needed for family.
Therefore, my self-counted score for diet, dating, financial planning, and employment decisions? Part credit for the dating and financial choices, a zero for diet choices, and 100% for family = 60%