... the more likely it is that you actually have an identity worth stealing.
And the more likely it is that you'll have a wealth of background to draw on when coming up with obscure-but-memorable (to you) bits of information you can combine and tweak to make a good password. I definitely notice this when comparing passwords my wife chooses with passwords my kids choose. She uses bits of old but important dates, parts of names of people she knew decades ago, etc. and comes up with some pretty good ones. I can mostly recognize where she got the pieces but doubt I'd ever be able to guess her password if she didn't tell it to me.
My kids, on the other hand, tend to pick simple names of favorite entertainment characters. Even when I try to get them to pick something more complex, they just don't seem to have much else to draw on. When I pointed out not long ago that one son's choice of his favorite pokemon's name as a password wasn't very hard to guess, he proceeded to pick a another pokemon with a longer name. When I talked him through the idea of picking several and using pieces of their names, the result was still not very good.
Perhaps all of this is just a result of not caring as much, but I think there's more to it.
(BTW, some are undoubtedly wondering why I force my family to give me their passwords. I don't. In fact I harp at them all regularly about how they shouldn't ever tell me their password. They roll their eyes and just blurt it out when I ask them to type it so that I can fix something on their account. I also find out their password when they forget their old password and I have to reset it for them. I used to change it to "changeme", but then I found out that just meant that my kids, at least, always had "changeme" as their password. So they actually have better security if I make them come up with something and tell it to me so I can set it. It also gives me a chance to make them think about whether or not they can remember the new password so I don't end up having to reset it again tomorrow.)