Why do programmers need private offices with doors?

frnanan

SubscribeSign in

Why do programmers need private offices with doors?

frnanan<br>Aug 20, 2026

Share

It’s a common occurrence: You’re sitting at your desk, lost in thought, trying to solve a problem that’s been blocking your work all week. Deep in your brain you’re building a structure of thoughts and possibilities undreamed of in anyone’s philosophy: You identify concepts and stack them against each other, turning them and flipping them and slotting them together. Like a keystone arch, as soon as it’s finished it’ll be strong enough to stand for generations—but it would topple to the ground in an instant if you stopped holding the pieces together before it was done.

A colleague comes along and notices you sitting there, maybe with your mouth hanging ever-so-slightly open, maybe with your head cocked sideways and one eye twitching and the general look of a person who has just inhaled a bug (just me?), and it’s obvious you’re not doing anything, so he taps you on the shoulder and says, “Can I just steal your brain for a moment? I wanted to ask you…”<br>And there, in that instant, the glorious half-arch you’ve been struggling to hold together comes crashing to the ground around you.<br>Like many of life’s most infuriating events, it’s easy to pin this one on people just generally being terrible. And hey, maybe people are just terrible. But there’s another theory which says it all comes down to miscommunication and different people accustomed to two very different kinds of work, so (in the name of charity and goodwill) let’s examine the generous possibility instead.<br>Brick by Brick

These two types of work were first identified, to my knowledge, by the programmer and essayist Paul Graham. The first type of work he describes can be interrupted harmlessly—nothing is lost if you stop for a second (or an hour, or a day) and come back to it later. An example might be building a simple pyramid out of wooden blocks (don’t pretend you don’t miss it). If someone wants to talk to you while you’re building your wooden pyramid you can easily stop, put down the block you were holding, and go off to chat for a minute or five; the tower will still be there when you come back, and you’ll have no problem picking up where you left off.

For a person accustomed to this kind of work, it’s obvious that if a colleague comes along and needs your brain for a moment, you should stop what you’re doing and help. Those 30-second interruptions cost them exactly 30 seconds, and what kind of person can’t spare 30 seconds for a friend in need?

The second type of work, however, is a completely different matter. The second type of work is like building our arch: If you stop for even an instant, you might drop half the pieces, drop the knowledge you were slowly accumulating of the strong points and weak points and which blocks go where. In these situations, a 30-second interruption can cost you a great deal more than 30 seconds—I’d argue, in fact, that for a Do Not Disturb task, a single brief interruption can easily halve your productivity.<br>Square by Square

Does that sound extreme, maybe even implausible? Here’s a (slightly) mathematical spin that I think shows why it’s credible. (Bear with me on the math, I promise it will be worth it.)<br>One way to think about harmlessly-interruptible work is that it’s any kind of task where productivity is linear in the amount of time you spend on it. That simply means that if you spend 2 units of time on a task, you get 2 units of output back. For linear-type work, it really doesn’t matter whether those 2 units of time are spent in an uninterrupted two-hour block or in two separate one-hour blocks, because 1 + 1 = 2. (You can check my sums, I’ll wait around.)<br>Once we see it this way, it’s easier to figure out what’s going on with the Do Not Disturb work. Do Not Disturb work is any kind of task where productivity rises in a variety of non-linear ways: For example (though there are many others), if productivity rises in line with the square of time spent. This could mean that a 2-hour block of work gives us 2-squared units of productivity, which is 4 units of productivity, but two one-hour blocks of work give us only 1² + 1² units of productivity, which is 2 units of productivity. Suddenly that 30-second interruption makes a huge difference:

As Graham puts it, for Do Not Disturbers, “The cost of having someone from personnel call you about a form you forgot to fill out can be huge. This is why hackers give you such a baleful stare as they turn from their screen to answer your question. Inside their heads a giant house of cards is tottering.”<br>Door to Door

As I said previously, I think that the simple misunderstanding between people who are accustomed to harmlessly-interruptible work and people who are accustomed to Do Not Disturb work causes many of the infuriations of the modern workplace. The harmlessly-interruptibles get exasperated at that one...