We probably all know the story about the fox and the grapes.

As the tale goes, the fox wanted the grapes on a vine above his head, thinking they were mighty tasty. Try to get them he did, but he couldn't reach them. Cursing he gave up and started going off on how they weren't as good as he initially thought.

The moral being it's easy to despise that which you can not get.

This is just a bit of commentary towards individuals who practice such behaviour when things don't go their way.