I understand how hard it can be to believe, after years of doing it one way, that you really don't have to spend so much time thinking about it and being paranoid, but you'll come to understand that most of it is handled for you. I hate to say "it's a matter of trusting Apple" because that sounds silly, but to some extent it's true. Obviously you still have to use some common sense and skepticism, but one of the reasons Mac users love their machines so much is that they have a certain level of inherent trust (or faith you might say) that the decisions Apple has made are by and large good ones, which is a very different feeling than you get from most other computers -- they put the weight of the decision-making on YOU (and of course some people much prefer that).