Request: Notes function on Emails

I would love to see a function where I could attach a note to an email in my inbox. For instance, I could right-click on an email to show a 'make note' button, and write myself a short note about actions / ideas / thoughts related to the email. Similar to a tag, but would not have to manage each new note as a new tag.

eg. "responded by phone on DATE"
or "Brilliant Idea!"

Thanks, M.