So Maude was (spoilers)
A Holocaust Survivor?
That certainly explains a lot about why she loves life so much.
On a side note, that's what I love about these older directors who understood that film is primarily a visual medium. A small detail, but one that opens up a humongous backstory and fleshes out the unseen history of a character.
Why can't all directors these days be that smart????
Limit of the Willing Suspension of Disbelief: directly proportional to its awesomeness.