Pretty simple answer for me...I'm a bit OCD (Obcessive Compulsive Disorder).
I tend to "charge" full bore at the things that interest me. Losing weight, I was on Calorie Count website several times a day. I could tell you within 10 calories what I had eaten on any day of the week. Didn't take me long to know how many calories were in the meals that we ate, or what I could order at a fast food place.
I'm the same way with crafting or anything else that grabs my interest. And yep. I'm a "gatherer" and a "hoarder"....thankfully William isn't, and he talks me into getting rid of stuff when I need to.