Self-help guru Dale Carnegie believed there was a little recognized secret of success . . . in a word: Enthusiasm.   He contended this powerful human feeling was the source of boundless energy that led to:

1. Setting and accomplishing goals;
2. Controlling worry and stress;
3. Better human relations;
4. Feeling more confident;
5. Developing leadership ability;
6. Becoming more results-oriented; and
7. Accomplishing more each day.

And an interesting dynamic to enthusiasm is its infectious nature and impact on others, and in turn you.  In other words, enthusiasm among a group of people can feed on itself and continue to perpetuate to unbridled enthusiasm.  When this happens though, be sure to keep your other emotions in check.

The below video illustrates how unbridled enthusiasm can sometimes get the best of you and cause unexpected results.