I suppose it is as if one were used to only bad things happening and when something good happens one lets it go because after all the bad things then a good thing does not seem possible. And either one convinces oneself that the good thing is a bad thing or one just turns it into a bad thing to prove oneself it was a bad thing and not a good thing. And one cannot really tell if it is a good thing or a bad thing or both. Maybe both. Maybe none.