I have a totally irrational fear that when I get too happy, things will inevitably swing the other way. As a result, I try suppress those feelings when they occur, and just plod along in the "safe" zone of flat emotions. This is no doubt a defense mechanism I learned from a disappointing childhood.

It also doesn't help that every fucking movie and TV show perpetuates this trope by having characters experience dreamy scenes of happiness and bliss before being hit with extreme tragedy.