My grandmother told me that "things happen in threes." Maybe. I would counter Grandma with "Things always happen, it's just easy to name three things when given the chance." What's far more difficult is to move up from three to ten. Though anyone can name three state capitals, three famous bald guys, or three things not to step in, it's more difficult to repeat the task with ten items.
Rest easy: I'm not asking you to come up with lists full of ten items. Instead, I've done that job for you: I've created some handy lists of tens, helpful information for any computer user. And I've put those lists in this part of the book, the Part of Tens.