When me and my brothers were little, we were destructive. One day, we were playing in the basement and broke the glass to a cabinet that belonged to my Mother's Grandmother. Years later as an adult, my brothers and I decided to replace the glass and get it restored for her birthday. We snuck the bookcase out of the house and hoped she wouldn't notice the very apparent absence of furniture. It was gone for 3 weeks and she never noticed. When we went to "give" the present, it still wasn't done and took her a few minutes of staring to realize what was missing. Once she figured it out, she cried for 5 minutes straight!