>>...(My daughters are both adorable but very easy to tell apart: one needs to be kicked in the behind on a regular basis and the other can be devastated by an unkind word.
>
>They must be dopplegangers of mine then!

Here's a perfect example where I lost the meaning because I didn't watch the context closely. I read this as "they are my doppelgangers", just as "friends of mine" means "my friend" (don't tell me I got this wrong). On second thought, I thought I'm not getting it, and tried to match how would two different kids be your doppelgangers at the same time. On third thought, I remembered that you too have daughters. Then I understood that "of mine" means "of the ones I have".