Can't pick just one, so....Yes. Been reloading since I was a kid and can't think of not reloading. Couldn't afford to not do it, wouldn't be happy with the quality of factory rounds, Wouldn't be able to shoot several rifles, and finally I really do enjoy sitting at the bench and loading.
I have always been interested in things that go boom. My pop started me out as young as I can remember helping him load up his bullets, then heading out to the range to try them out, I guess I never knew better. We always picked up at least two boxes of factory ammo for most new rifles we got, simply for comparrison, but that was about it for factory loads.
I like a challenge, and as Roy mentioned about doing it your self, just something else I learned growing up. I realize that there are limits to my abilities in many areas, but in reloading I feel I have excelled. The biggest reason I load now days is economy, I simply hate to pay what the stores want for a box of shells. Heck I even hate to pay what they want for just a box of bullets anymore, and am glad I picked up bulk quantities when I found something I liked. I do however still pick up factory ammo for a couple of rifles simply due to the fact that those particular arms shoot it so wonderfully, I just haven't even bothered to work up loads for them.
I began reloading when my two sons were old enough to hunt. Keeping their shotguns fed kept us all busy.The biggest advantage was the ability to download shells for them when they were young.Also .410 shells were never on sale and went for 6-7 dollars a box and I could reload them for almost nothing.Ireload rifle and pistol rounds for accuracy and economy.Some guns just don't shoot well with factory loads.
You left out: "Because it helps to satisfy in me a primordal desire, akin to knapping out a flint arrowhead, or scraping and testing shafts for straightness. Anticipation of the coming hunt, knowing that part of my spirit will fly with the bullet, is the reason I reload. Or, as someone already said, "Because I can."