Does it actually make any sense when someone claims that they wish they were born in a different era or location or to a different family?
Sometimes, someone will say that they wish they'd been born in, say, 1950. Without thinking too hard about it, it seems to make sense. But if I do think about what they said, it really doesn't.
Let's say we have two timelines. We have the first one in which the person says they wish they were born in 1950. And then we have the second one in which, for whatever reason, there was one more person born in 1950 that wasn't born that year in the first timeline. The problem I see is that there's really no way of linking these two people. Who's to say if they're "the same"? They'd have different experiences, different looks, and probably different personalities.
I could see this maybe being resolved by throwing in the concept of a soul, but that doesn't really seem like a logically-sound option (if you and I (as souls) switched bodies for the day, would either of us be able to tell in the moment, or the next day?).