OK, I know there's a TON of threads about refurbs and I have read through as many as I could find. Some of you have said your refurbs came with "surprises" such as extra RAM and whatnot. How does this happen? Are they upgrades from the previous user or something? Also, is there any other reason not to get a refurb MB other than it's not "brand new" and doesn't come in the same packaging? Thanks! Hoping to buy my first Mac sometime soon.