I Thought I Understood Bitcoin. I Was Wrong

There's a version of knowing something that feels like understanding but isn't.

I had that version of Bitcoin.

For a long time, I could talk about it confidently. How it works. Why it matters. What makes it different from everything that came before. I wasn't making things up. But I also wasn't telling the full truth — because I didn't know it yet.

I was describing the car by pointing at the wheels. I had never looked inside the engine.

Seven weeks ago, I joined the Btrust Builders Mastering Bitcoin self-paced cohort. I expected to fill in a few gaps. What actually happened was different. The gaps were bigger than I thought. And the things I assumed I already knew were often the things I understood the least.

Chapter 1 Should Have Been Easy

I expected Week 1 to be review.

It wasn't.

The first thing that stopped me was double-spending. I had explained it before — Bitcoin stops you from spending the same coin twice — and moved on like it was simple. But sitting with the actual mechanics of how that works, with no central authority, with strangers across the world who don't know or trust each other somehow agreeing on one shared history — I realised I had been skipping past the most important part every single time.

The Chapter That Embarrassed Me

Here's something that genuinely embarrassed me.

When I got to Chapter 9 — transaction fees, I discovered something I had been getting slightly wrong every time I explained it.

Bitcoin transactions have no fee field.

None. It doesn't exist in the protocol.

The fee is simply whatever is left over after you subtract your outputs from your inputs. If you send 1 bitcoin and create outputs totalling 0.9999 bitcoin, the miner takes the 0.0001 that remains. If you forget to send change back to yourself, the entire remainder goes to the miner. There is no prompt. No warning. The protocol just takes it.

I thought about how many times I had explained fees as "a small charge." That framing completely hides the truth. It's not a charge. It's a bid. Every transaction is competing with thousands of others for space in the next block. Miners pick the highest-paying ones. Your transaction is an auction entry.

I rewrote my mental model of fees from scratch that week.

Security Taught Me Something About Myself

Chapter 13 — Bitcoin Security, made me uncomfortable. Not because it was complex. Because it was personal.

Bitcoin security is not like bank security. A bank is designed to protect you from your own mistakes. Bitcoin is not. Bitcoin cannot. If you lose your keys, there is no recovery. If someone steals them, the transaction confirms and the network moves on. The same property that makes Bitcoin uncensorable — that no authority can reverse a transaction — makes your errors permanent too.

The book describes a real event: a well-known Bitcoin project lost nearly 7,000 BTC in 2011. Not from a hack. From over-engineering their own backups. They encrypted everything so aggressively they locked themselves out. The protection destroyed the thing it was meant to protect.

I sat with that for a while.

Possession of the private key is ten-tenths of the law. Not nine-tenths. Ten. There is no appeals process. No customer service line. No one coming to help.

That kind of responsibility is heavy. But it's also honest. And I'd rather have an honest system than a comfortable one.

What Actually Changed

Before this cohort, I could talk about Bitcoin.

After it, I think in Bitcoin.

There's a real difference between those two things. Talking is surface movement. Thinking means the mental model is underneath everything, quietly organizing how you see new information. When I come across a new Bitcoin product or proposal now, I automatically ask: what primitives does it use? Where does trust live? What happens if one party disappears or tries to cheat?

I also know more precisely where my understanding ends. Week 1 I asked: will Bitcoin ever replace fiat? Looking back, that was a spectator's question. The questions I'm asking now are builder's questions. Better questions are the real sign of learning. Not better answers.

WHAT'S NEXT

I'm building BitcoinLasgidi — a Bitcoin-focused community on my campus in Lagos. We educate developers, designers, builders, and enthusiasts about Bitcoin. Everything I learned in these seven weeks goes directly back into that work. The way I explain keys, fees, mining, Lightning, none of it will sound the same as it did before.

Now I know how much there is still to learn, and how much more there is to build.

That's the best possible outcome.

Let Bitcoin Lead. 🧡