I don't know whether this is cool or sad. Fallout 3 passwords were trivially easy to infer from a single guess. They took extra time to reduce the ambiguity and make it easy once you understood the principle.
I think it's probably more on the side of "sad", considering the way I did it. No mods. I wrote a little android app that you could put the words and number of correct letters each try into and it would shorten the list each time you did.
After a while I figured out "the trick" and could do them in my head and didn't need the program anymore. It was a fun little programming exercise, though.
Were you running a mod?