Your brain was the bottleneck

Mark Zuckerberg wears the same gray t-shirt every day. It sounds like a quirk, but when he explained it in 2014, the reasoning was precise: “I really want to clear my life so that I have to make as few decisions as possible about anything except how to best serve this community.” This sounds like eccentric CEO behavior, but there’s real science behind it.

It is called ego depletion. Your brain has a budget for decisions, and every choice you make draws from it. Working memory holds only 3 to 5 items at a time. Every choice you make, however small, draws from this pool. By afternoon, knowledge workers are measurably worse: they type more slowly, make more errors, and their judgment deteriorates. A famous study of parole judges found that favorable rulings dropped from 65% after a break to nearly zero by the end of each session.

I used to think AI tools were just faster versions of what I could already do. ChatGPT felt useful but limited. You had to prompt carefully, copy-paste between windows, iterate manually. It helped, but it didn’t transform anything.

Then Claude Code got released.

The interface is a terminal. You speak or type what you want. The AI figures out the plan, executes it across your entire codebase, and shows you the result. You review. If something’s wrong, you say so. It iterates. You’re not making thousands of micro-decisions about file names, code structure, or implementation details. The AI handles all of that. You’re just reviewing and steering.

Here’s what surprised me most: I can work for hours without getting tired.

The slump after a highly intellectual task, that familiar crash where your brain goes fuzzy, doesn’t hit the same way. My cognitive budget is being spent on what matters: evaluating ideas, spotting problems, providing direction.

I think we’re seeing the beginning of a fundamental shift. For decades, productivity tools helped us do things faster. AI tools are different. They don’t just reduce the time per task. They reduce the cognitive load per task. And that changes what’s possible.

The feeling of having unlimited mental energy is genuinely addictive and everyone I talked to seems to feel the same way about these AI tools. People wonder why everyone working with Claude Code or Codex is obsessed with it. This is why. It’s not just that they’re fast. It’s that they remove the tax on thinking.

This has implications. Work will get more intense, not less. If you can sustain peak output for 8 hours instead of 4, employers will eventually expect it. The creative who used to crash at 6pm will now push to midnight. The startup founder who burned out his employees doesn’t have to recalibrate so much anymore.

But the capability is real. For the first time, the bottleneck isn’t your brain.

It’s what you decide to point it at.