I get where your coming from, but the way I see it, in order to devine the pattern I use, the cracker would need to crack/obtain at least two examples of current or previous passwords I have used. Even with two examples, you'll have to take my word for it that the pattern is very non-obvious as doesn't relate to dates, times, places or people, or any personal information, nor is there any mathematical relationship involved.

Anyway, if the cracker get a hold of two of my passwords, they would pretty much 0wn5 m3 anyway:^)

T'is a good thought though.