The next time you meet some person who is utterly captivated by some undertaking that completely mystifies you, give him the benefit of the doubt. Hold back on your instinctive imputing of excess spare time and hang the obsession in a tickler-file in the back of your brain to pull out and think about in the shower or the post-office line. If you’re very lucky, a little of that delight may rub off on you, too.