Depends on who you ask. My family rolls their collective eyes at me most of the time. My friends laugh with me. Being silly is painting and alligator Magenta with Chartreuse spots because I can. Being silly is laughing til you cry over the stupidest jokes. Silly is wearing umbrella hats to soccer games, mortifying the kids. Silly is two Grandmas trying to chase down a rolling car, recounting the story with hilarious details (lots of eye rolling there).
For me being silly is not taking yourself too seriously. Just walking on the lighter side of life Not fretting over those little annoying things that scatter through my day. Too much time is wasted being annoyed life is too short. I look for the joy. The silly.
