It sounds like you're conflating caring about the quality of ones work with having a poor work-life balance.

Also, I think that pursuing happiness in and of itself is quite boring and demonstrates a lack of agency that we have as human beings... We need more than just the feeling of constant pleasure in order to have a fulfilling life. One very basic example: if you were happy all the time, how would you actually know? Being aware of the contrast between various emotional and psychological states provides a lot more fulfillment versus always residing in a single mode of existence.