I learned that putting more pressure on myself wasn't working, that there isn't a linear relationship between pressure and results. Instead, there is what I call a sweet spot, beyond which more pressure decreases results instead of increasing them.
This. Elon Musk is quoted (?) as saying "If you work 100 hours while others work 40 per week, you can do in 3 months what they do in a year." But the truth is that overwork leads to unproductive work, burnout, and loss of passion.
I'm definitely most effective when I'm happy. If I overwork myself, I quickly get into a negative feedback loop of "never being caught up and satisfied with work."
I learned to internalize the idea of keeping myself happy (stable work/life) first, as in the long run this is the most effective situation.