PG I suspect and many others derive intrinsic happiness from the grind. From achievement. Yet this is a very myopic way to live that for the vast majority of people will result in a fair amount of unhappiness.
A far healthier and happier way to live is to live a balanced life. Work efficiently when you need to work, and be focused on your objectives. Don't waste time on stuff that doesn't matter. You can still be successful, grow yourself, etc. but without killing yourself in the process.
And for the love of god... take time for yourself to enjoy the finer things in life. Take a walk and try to find the beauty in things. Go travel somewhere new! Enjoy some you time and treat yourself.
I cannot disagree more with PG here, sadly. But that's all it is... a disagreement. Everyone gets to choose what life they want to live.