I found this video. In it, Dr. Brene Brown explains why I dampen joyful feelings with images of loss... and that instead, I could practice feeling gratitude in those moments in order to experience true joy. She has done a lot of research on vulnerability, and in order to feel joy, you must be vulnerable... but, because you also must be vulnerable to experience all other emotions... we try to avoid painful emotions by escaping from vulnerability which leads to numbing all of our emotions.
This is the video that really gets me excited to start practicing gratitude, I guess because it tells me what to do when I feel joy, instead of shoring up my ability to accept a loss that I feel is imminent. I'll start now, with "I am grateful for this video!"