The reason why diagnosis on adults has been more nebulous is that a lot of the traits are merely well-adapted to by adulthood. so only the truest experts have been able to determine how to approach adult diagnosis.
Beyond just looking at controllable encounters to intellectually develop a controllable response, how does one approach things in the "core" of one's personality that aren't actionable? How would I approach vicariously feeling what someone else is feeling so I can detect when it would be a good idea to use emotion-repairing strategies or when it would be over-reacting? A big part of the issue is not sensing the signals that most people would intuitively (without conscious deliberation), which throws you off in any unfamiliar scenario.
The symptoms I've grown out of are both explained by increased self-awareness
1. Picky eating - I still am considered picky by most. The difference is that I perceive I only feel like eating certain things at any given time. I've only just recently noticed how I do this, sort of auditioning food in my thoughts. I make sure to eat those things that I feel like eating instead of trying to force myself to eat something I won't be able to. I have a set of preferred foods I stick to, making shifts from time to time (as my tolerance tends to break down. Suddenly one day I just cannot eat what I have been recently).
2. Impulsiveness - This I view as a natural part of my adolescence. I've noticed the older I've gotten that I always get lost on focused details. My lack of big picture perspective throughout childhood explained most of my out-of-control behaviors. As I now see a longer view of my own personality, I've become more baseline, in control of the actions I choose, and more often finding myself the opposite of restless-- but come across very calculating, even intimidating to some. I've become such that I simply avoid action when I can.