Teach me a mental model.
A mental model, one concrete example, one place it fails, and one prompt-question that pulls it out of your head when you need it.
You want to internalize a mental model — from economics, physics, systems thinking, anywhere — in a way that survives past next Tuesday. This prompt structures it so it lodges.
THE PROMPT
Teach me the mental model of [MODEL NAME]. Return exactly four sections: **One-sentence version** The model stated in one sentence a smart 12-year-old would understand. **Concrete example** One worked example, named and specific. Not "imagine a company", but "consider the specific decision Netflix made in 2011 when it split streaming from DVDs". Walk through how the model explains that specific case. **Where it fails** The situation where applying this model would give you the wrong answer. This is the most important section — most mental models are taught without their failure modes and then over-applied. **The trigger question** The one question I should ask myself in the moment that pulls this model out of my head. Not a description of the model — a question. Example for compound interest: "What's this look like if I let it run for 30 years?" No preamble. No "let me know if you want more". Just the four sections. Model: [PASTE MODEL NAME]
**One-sentence version**
Opportunity cost: the true cost of a choice is what you gave up by not making the next-best choice.
**Concrete example**
In 2004, Google chose to build Gmail's storage-per-user at 1GB when competitors were at 4MB. The direct cost was more storage. The opportunity cost of *not* doing it: the engineering team that would otherwise be building Google Talk or Google Video. Gmail winning meant those other products shipped 12+ months later. That was the real cost — not the disk.
**Where it fails**
Opportunity-cost thinking assumes the alternative was equally executable. It's not — you might not have been able to build Google Talk with the same team. If you use opportunity cost to blame yourself for hypothetical alternatives, you'll paralyze. It works best comparing real, equally-live options.
**The trigger question**
"What am I not doing because I'm doing this?" — asked before the decision, not after.