Joe brought some soft drinks home one afternoon and put them in the fridge. The fridge was probably older than he was, so it was a bit unpredictable - you never really know what the temperature is on the inside. So to make sure his soft drinks were cold enough for drinking later, he turned the knob all the way round to the snowflake picture. Satisfied, he went on to do some house chores. Since he lives alone, he has to take care of everything in the house so the work always piles up.
A few days later, Joe opens up the fridge to look for some eggs - it's breakfast time. He grabs two eggs and brings them to the counter, to make them into an omelette. Somehow, the eggs don't break despite a small crack in the skin - and he finds out why: the fridge, being too cold, actually froze the liquid insides of the eggs. So he forgets about the omelette, puts the eggs back in the fridge and dials down the temperature control 2 notches.
Another few days later, when clearing out the fridge, Joe finds the egg with the hairline crack - he completely forgot about it. He looks closer to the crack, while unconsciously pressing the egg, and SPLAT!
Sure enough, the crack widens, and the egg is generous enough to splash all it's contents to Joe's face. Joe is stunned for a few moments, before feeling stupid. Thankfully, there are no witnesses.