I love playgrounds (and it is not because I have a two year old and playgrounds can entertain him for hours - always a good thing). I love them because kids on playgrounds are happy. They get to run around, climb, slide, swing and laugh. They are free for a little while to have fun - no cares, just immediate fun.
As adults, I think we forget to have that time and place for ourselves. We need to have that space of freedom, it is so important to our sanity. We need to have a place where we can laugh with no worries. Find that place - that place of innocence where you can be you and have some fun and laughter.