What's the point of "repairing permissions"? I mean, I heard everyone talk about it when I bought my PB last year, so I've been going thru Utilities and doing it, but I have no clue what's the point of it. I do "Repair Permissions" about once a week, and I always see a HUGE list of "things to repair"! What is going on???? Any explanations would be great... sorry, not exactly a software genius!