Why do people love to solve puzzles?

"When solving a sudoku (a logic puzzle requiring players to place numbers in rows and columns) quickly, it helps to be young. The Chinese champion was just 14 years old; the youngest contestant (from South Korea) was merely 10. Gareth Moore, one of the organisers of the competition, reckons that, once you have passed your early 20s, your best sudoku years are behind you. But that does not mean the rest of us should give up having a try. There is some evidence that attempting puzzles of various kinds is good for our long-term mental health. In particular, it may ward off two of the great scourges of old age—dementia and Alzheimer’s—at least for a time."
http://www.economist.com/blogs/buttonwood/2014/12/brain-training

Check out this Vibrant Mega puzzle on ebay
http://www.ebay.com/itm/Vibrant-Mega-Puzzles-1000-pieces-View-Through-the-Woods/192086948141#shpCntId