Twenty reasons why you should never be instantly available. Every hard worker knows the sheer ecstasy of logging onto one’s work email and switching on the “out-of-office” alert system before a big trip. (Honestly, is there any better feeling?) But when you travel as much as I do—as a self-employed writer, I spend practically half my life at 30,000 feet and on foreign soil—you learn a dirty little secret: you should never, ever, ever, turn that alert off. Seriously. I don’t. My out-of-office alert is activated regardless of whether I’m in China or I’m sitting at my desk in my New York apartment. Yes, it’s activated right now, thank you…