I kind of had the feeling I could write code for a Mac and ship it.
Wait, in some sense I have done so before with code for computing fractals I shared with other Mac users in my department. It worked perfectly in my Mac and their Mac.
Wait! I have downloaded and paid for apps straight from some developers websites (top of my mind, or top of my menu bar: Hazel, 1Password, Arq)
So I just stopped my reading there, sadly.