I have been making happiness my default feeling for the past year and I can promise you that it is not mundane and it has only enriched my life. Life is better when you Feel Happiness
When bad things inevitably happen in your life choosing to be happy about it is pathological. Someday your parents are going to die. Friends will betray you. You need a better plan.
Bad things will always happen, sure, but focusing on the bad only makes it worse. Finding the good within the bad brings better perspective/insight. It’s not pathological at all.
When my parents eventually die, I will be grateful and happy for the many wonderful years we shared. When a friend betrays me I can be happy for all the joys we shared & hope them well