I have noticed that if I look back at the traumas in my past which have impacted my ability to be happy in the present, there is no difference between events I perceived as "extremely bad" in the past vs "extremely good". Both have affected my ability to be happy now because the bad events left lasting fear but the good events have left lasting desire and dissatisfaction because nothing else can measure up. Both good and bad things happening are a form of injury if you really believe them to be extremely good or bad. I imagine someone who wins the lottery might get depressed years later because they will never have another day as "good" as that one.