I think the biggest thing for me has been the fact that there is nothing actually wrong with me. Specifically:
10+ years struggling with depression = ended up being largely due to gluten, perhaps some general systemic inflammation as well.
Seasonal allergies, acne, perpetual digestive problems, several food allergies/sensitivities = all largely leaky gut related.
Slowly but surely disappearing tooth enamel = I hadn't eaten dairy in 10 years due to "lactose intolerance" (which is gone now, thanks healthy gut flora!), nor did I consume animal fats. After a year of eating lots of good sources of animal fat (dairy included) and avoiding sugars, my teeth have never been stronger.
So many little things that I wouldn't have sought a cure for specifically: little aches and pains, getting a cut on my finger and it taking four weeks to heal, never being able to gain muscle, white spots on my toenails, the perpetual little bit of belly fat, constant reminders from my doctor that I was anemic... all are either resolved or significantly improving. My overall quality of life and sense of self confidence has never been better due to all these little things; I can't help but feel more and more optimized every day.
I was always the kind of sickly, allergy-ridden, overweight kid, growing up - and even after I lost 100 lbs (on CW for the most part - around age 18) I had the above issues still, which I had just decided were "the way life is." It has been such a continually surprising and rewarding journey, discovering the power of real food - and discovering that I am not genetically broken, just a bit malnourished from growing up on 80's - 90's low-fat propaganda.