Yesterday I managed to explain it all to a friend. With graphs, saving rates, interest rates and all. And he got it.
This was a triumph.
I'm making a note here, huge success.
It's hard to overstate my satisfaction.
I'd be very interested in seeing those graphs and what not. I have a relatively solid method which is just a spreadsheet, but it lets me figure out if they understand it or don't. Was this person resistant to the idea and you turned them, or neutral, or what? I love hearing stories like this, and details would be awesome.
I have really nothing, just tried to make him understand a small set of key ideas using a pen and a piece of paper as support.
The first one of these ideas was that "the rewards for saving grow exponentially but they are hardly noticeable unless you stay north of 50%". At this point I used the paper to illustrate what happens over time when you save 10%, 20%, 50%, 66%, 75%, 80%, 90% and 95% of your income. Notice that this is just a simplification of The Shockingly Simple Math Behind Early Retirement, a post from MMM that absolutely blew my mind at the time.
Once he was hooked we moved towards the concepts of annuity and SWR, then used the pen and paper to do some back of the napkin calculations to find out his "number" and how long would it take him to reach it using different variations for expenses, interest and savings rate.
IIRC the thing with what he struggled the most was thinking of his savings in terms of "years of expenses saved" and understand statements like "with a 4% interest rate you need 25 years of expenses to retire" instead of thinking in absolute numbers, but he eventually got it.
When we met again after a few days he told me he had been having trouble sleeping at night, thinking about all the implications of what I taught him :)
Have to admit though that he was actually interested in what I was up to and approached the whole thing with an open mind. Unfortunately you can lead a horse to water, but you can't make