I found that people who don't go to work tend to be more energetic.

The kind of very proactive and positive people I know mostly don't work.
Friends who do work used to be very sunny and cheerful; they were high school teachers in China.
Now, after work every day, they just lie in bed reading CEO novels and short dramas.
She used to be a graduate student in world literature, and even had an underground band in Shanghai.
She was once a very artsy girl.
Why do you think this is?