There are many items that separate, are relatively harmless. However, mix them together and the outcome is sure to be anything but good.
Vinegar and baking soda.
Suntan oil and beach sand.
Fingers and car doors (or ladders).
Hair spray and aromatic candles.
Waxed linoleum and stilettos.
You get the idea?
Here's an example when you mix a young child and a pair of nail scissors:
And I'll be damned if the little shit didn't do a pretty good job, considering, as you may be wondering what the heck the big deal is about. Below is a picture WITH his boy bangs (or the "Before" shot):
So if your kid tells you he or she going to go brush their teeth and doesn't reappear within just a couple of minutes from the bathroom, it's a good idea to go check on them, even if it means not reading blogs for a few minutes during the quiet evening hours.