A stag had grown thirsty and went to a spring in order to drink some water. When he saw the reflection of his body in the water, he disparaged the slenderness of his legs but revelled in the shape and size of his horns. All of a sudden, some hunters appeared and began to chase him. As the stag ran along the level ground of the plain, he outdistanced his pursuers and beat them to the marsh by the river. Without thinking about what he was doing, the stag kept on going, but his horns became tangled in the overhanging branches and he was captured by the hunters. The stag groaned and said, 'Woe is me, wretched creature that I am! The thing that I disparaged could have saved me while I have been destroyed by the very thing I boasted about.'
Lesson: This fable shows people should not praise themselves for something unless it is useful and beneficial.
This and other Aesop's fables can be found here.