Dreaming of parks and carnivals mean you are recalling extreme emotions of happiness and frustrations. You may have spent an awesome memorable day at the park with a significant other and continue to cherish the moments.
At the carnival, you may have waited hours in line for a 2 minute ride. That’s the frustration you remember, in addition to the thrill you had on the ride.
These extremes help to make life feel real; and you want to experience them again and again.