There's a strong mostly unspoken current in Japanese culture not to get too excited by some relatively transient boon. It's not something people talk about very much --- it's just the way people behave and you kind of absorb it by osmosis over time. I've thought about this and the interesting thing is I don't think it's so much driven by a desire to be virtuous or self-denying as it is more a kind of realism or strategy for happiness over the long haul --- a sense that any up can be followed by a down. I.e., it's one thing to get rich quick, but another form of wealth is to just have relatively modest needs and therefore no matter what happens, you'll be okay.
My mother once came home after these con artists (in LA) tried to bilk her out of her bank account; it was an elaborate scheme where they showed her a pile of money in a bag and then made up some story about how they needed "help", and implied my mother could get some money out of it, which of course eventually involved going to an ATM so she could show a supposed recent immigrant that "in America, even minorities can have bank accounts" or something like that. My mother was never even slightly suspicious but decided she didn't want to do the ATM thing, even though she didn't suspect anything, so they gave her her stuff back (they had taken her cell phone). My mom came home worried about who was going to "help" these people. Of course, I just started laughing when I heard her story and said she is so naive! But the funny thing is, she is also so ungreedy, having no interest whatsoever in the money they were offering her for her "help", that the con totally failed on her.