The answer is NO. We should not try to be happy all the time:

There are disadvantages to positive thinking, advantages to negative thinking and to be at our best we should use the right tools at the right time.

Specifically, in a competitive context, happy isn’t helpful.

Eric Barker's article explains why.

My favorite part of Eric's article is below.

Via Top Dog: The Science of Winning and Losing:

The problem is that what’s good for your well-being is not necessarily going to be effective in a competitive context, or help you sustain the drive to achieve your goals.

In the well-being realm, traits such as ambition, dominance, and perfectionism are considered psychological maladies that need to be treated. But during a performance, or when striving to achieve goals, they can all be adaptive. It bears repeating: 

The mental states needed to compete are not always socially palatable. When the object is to compete, positive psychology becomes a handicap. Its Panglossian ban on negative thought denies the value of critical thinking about past performance, which is necessary in order to learn from one’s mistakes and alter strategy going forward.

There is a time and place for negative emotions.

If you leave them out of your toolbox, you may be missing something good.