When to use it
Use it in the thank-you email you send after an interview. Mention one specific thing you discussed and why it made you more interested. It shows you were engaged and helps the interviewer remember you.
Example
Your note: “Thanks for today. Our talk about the new client portal made me even more excited about the role.”
Your note: “I'd love to help with the launch. Looking forward to next steps.”
In an email or Slack message
Send it within a day. Keep it to three or four sentences: thanks, the specific moment, why you're a fit, and next steps.