I was told once that a password should be something that means something to you, but no one else

So I used my first girlfriend's phone number with a suffix of the date we first had sex, for quite some time. A very memorable date.
Then I used her postcode with the date as a prefix...

Then I was told by SWMBO that this was inappropriate, even though they date from the early 1970s....
So now I use SWMBOs postcode and date in the same way. Seems that this is acceptable...you can't win, I feel...