The conclusion is not obvious:

Almost 50 percent of respondents who feel least rushed and who also feel least excess time report being “very happy”, almost twice as high as the rest of the US public. It is an elite group, making up less than 10 percent of the population. They not only seem happier by ignoring the “rat race” and subscribing to a philosophy of “Don’t hurry, be happy,” but by organizing their lifestyles to minimize spells of boredom and lack of focus as well. Thus, there seems dysfunction in having either too much or too little free time.

It's really hard to strike a balance between being bored and feeling rushed all the time.

But those who can do it are very happy.

Yep. Pacing.  The only modification I allow to my only two rules in life:

Rule 1. Smile

Rule 2. Ask

Modification:  IF Smile and Ask aren't working THEN either slow down or speed up the pace.  

Most all of my successes have been achieved by aligned pacing that created better harmony in whatever collaboration with Life I'd desired and intended as my next emergent reality at the time.