While it sounds counterintuitive, for many people - myself included - feelings of joy & fun are the most difficult to embrace. Elation and laughter and pleasure can trigger the vulnerability warning alarms when you have experienced life through the lens of hypervigilance, survivalism, and trauma.
In childhood, we learn how to keep the lines of attachment to our caregivers strong, even and often especially if our innate authentic behavior leads to negative repercussions. For example, the toddler whose giggles elicit a response of "be quiet" or "shut up" or the school age child who gets in trouble for being too energetic and generally "too much". People who grow up in less stable homes, who lack the basics of shelter & food as well as loving touch and attunement (which are often not considered) can find joyous expressions and feelings uncomfortable, or even downright threatening.
What makes joy dangerous? I can't speak for all, but there are a few layers to it in my experience. First to mind, is that it wasn't something that was modeled for me - I didn't often see my parents smile or laugh. Because of the unstable way I grew up, day to day life was unpredictable, so I cultivated hypervigilance as a survival strategy - Spidey Senses, if you will - to keep an eye out for bumps in the road. To feel joy required me to let down my guard and to have a sense of safety and security that I wouldn't find until adulthood.
Taking the time to understand what's underneath the surface of our current existence is a crucial piece of personal growth. Healing from our past experiences isn't an instant gratification process. Sometimes you might not even have words for what you feel. The path can be hidden, messy, painful, and long (unending, actually) - but from someone who has traversed some miles on my own journey, it has been well worth it.
It's been through unpacking and processing, asking for help when needed, allowing myself to feel, and intentional practices meant to expand the personal boundaries of comfort that joyful expression has begun to be something to embrace as opposed to shy away from. The laughter and silliness of my children seems a little less foreign and confusing as I join them instead of just watching them. As I continue my campaign to come home to myself, the colors and variations of this day to day human experience become more vibrant and I become more engaged and open to allowing all that this life has to offer.