See the gorilla experiment with the basketball.
Secondly you have acceptance, which is different from gratitude. In a bad situation acceptance is really referring to not attempting to remove painful thoughts. So instead of removing painful thoughts with thoughts of gratitude, you are accepting of the painful thoughts and converting your emotional response into resilience, fortitude, growth, and ultimately to live a life which is aligned with your life meaning or your core values.
You might also in some instances be grateful for the opportunity for growth or the lessons learnt but this is definitely not to be confused with accepting painful emotions, and expanding your ability to contain them an act effectively in the world.
Hope this answers your question.