This weekend was the World Athletic Championships in Berlin, Germany. The women's 10,000m final was very interesting if you read this post at letsrun.com. Meselet Melkamu started celebrating a bit too soon (6 inches according to letsrun) and Linet Masai squeaked by for the win - by 0.1 second. Gold medal gone, just like that.
A couple of years I posted a link to another case of premature celebration. That one made the difference of bragging rights to the Chicago Marathon and an extra $60,000.
Moral of the story - unless your last name is Bolt, you better not start celebrating until after you've crossed the tape.