Re: Multi screen
My eyes move. That's what they do. It's almost like they have muscles to do that with.
They read one line of text at a time. Now, admittedly, they can be aided by certain-length text and certain arrangements of text, but a dual monitor *does not* stop them needing to move. It just makes them have to move further, in fact. Especially the portrait monitor thing - that baffles me. I'll give you a small exception if you're doing full-page previews in a desktop publishing job. Otherwise... you can't see all the screen at the same time anyway, and your eyes move.
Thus, with a tiny, tiny, tiny piece of training, you are able to put any text you want to read smack bang in the center of your vision in fractions of a second. If you want to compare spreadsheet rows, you can side-bang the windows (in modern Windows) and line them up side by side in seconds. Or use different Excel views. And then your eyes compare left-to-right, left-to-right.
You are enforcing context changes that involve head and neck movement and a longer range of eye movement, where the same job is perfectly viable without such things... moving the data under your eyes.
Anecdotally, all the people I know who "have to have" dual monitors work just fine with one when they realise they aren't getting a second. All the people who *see* someone with dual monitors suddenly want one (status-symbol-itis), even though they have no idea whatsoever about how to arrange windows (i.e. they use dual-monitor, with only two apps, one per screen, but don't maximise either - or they lose an application because they don't know which monitor it's on, or they end up using the second monitor to "get windows out of the way" of the primary monitor, and so on). Without exception, those people don't know Alt-tab, side-banging of windows, split views in Excel, etc. etc. etc.
And are you watching the movie, or are you browsing? Because you can't do both simultaneously (unless your eyes are capable of separating), so you're ignoring the image of one to look at the other. So... you may as well switch windows and then switch back.
Screen real estate literally doesn't matter. Your eyes only see a tiny portion. As I look at this screen typing this, without moving my eyes, I cannot discern with any accuracy the shape of the text just two lines above... a few dozen pixels. It actually takes a lot to FORCE my eyes not to move to read it. Watching a movie, I'll give you, because you want "suspension of disbelief" where the movie fills your vision and more no matter what your eye chooses to look at. But PC and text work... that's an entirely different matter.
It's not a case of different wants. I do basically every job that's possible on a computer - web design and browsing, system management and monitoring, long text documents, complex spreadsheets (finance systems), technical documents, novel-writing, gaming, movies, coding... I live on all my machines and all my machines have only one screen. Second screens - when I work on a machine with one - go unused. It's a case of a working practice that doesn't rely on having a second screen, a working practice which makes any job possible, and virtually every job happen faster/smoother than someone whose job it is to do that all day long (I guarantee you that I can out-spreadsheet the finance department, because they ask me all the time when they get stuck knowing that I can do that much more quickly).
And I have the complete choice of whatever I like as I "have to" specify entire networks and supply some users with dual-screens, so I can easily have whatever hardware I want for my own PC, I could specify almost anything, authorise the purchase, order it myself, have it delivered, asset-tag it and keep it on my desk and nobody would ever be any the wiser and it would never get questioned. And it's just not worth having a second screen.
You've taught yourself to be reliant on a second-screen that you can't utilise simultaneously with the first (unless, I would suspect, it was part of a monitoring wall, at a distance, to show up flashing red flags for systems that were in error - in which case we're not talking desktop-PC-with-dual-monitor but that you should just have a monitoring PC with its own screen independent on anything you might do with Word on the desktop) and then convinced yourself that flicking your head/eyes between two screen of different location / size / brightness / angle / focus-depth / orientation(!) is somehow better than doing the same, on a bigger monitor, over a single surface. Or even, barely moving your eyes at all and putting the data you need to see underneath them (via Alt-tab, side-banging windows, etc.)