If you’re still confused, remember this: The introduction answers “Why should I read this?” The summary answers “What did we just learn?” One is a question, the other is an answer. Mixing them up is like putting on your shoes before your socks. It’s just… wrong.
When you write next, try this: Write your summary first (get it out of your system), then delete it. Now ask: “How can I lead the reader into the water without telling them how deep it is?” That’s your introduction. It’s a tease, a promise, an invitation.
Final ironic side comment: If you skimmed this whole article looking for the key takeaway, congratulations—you just used the summary mindset. But if you actually read from the top, you just experienced a proper introduction. The choice is yours. Now go write something that makes people curious, not something that makes them check their watch.