Frankl is the canonical example. But also telling is the portion of Spiegelman's "Maus" which tells of his release from Auschwitz, entitled "And now my troubles began..."
Spiegelman's father, not him. Downvote all you want, but trying to find the positive side of of concentration camps, trying to find why you're world view is validated by anecdotes from those experiences, its really lame.
I know it is Spiegelman's father: it is a memoir of Spiegelman Sr's experiences, as told to Spiegelman, but that's neither here nor there.
The point is not that anyone is trying to find the positive side of concentration camps, as if such a thing existed. The point is that some people managed to keep their spirits intact, and, in the words of the poster above, find peace, meaning and value in their lives even in the worst condition imaginable.
Is it lame to remember that even when we can't control our external circumstances, we still have some ability to control our response to those circumstances?