From Paul Graham’s fantastic blog post How to Do Great Work:

“It’s not necessarily a bad sign if work is a struggle, any more than it’s a bad sign to be out of breath while running. It depends how fast you’re running. So learn to distinguish good pain from bad. Good pain is a sign of effort; bad pain is a sign of damage.”

Distinguishing between flow state and over-exertion is one of the most critical skills for long term growth – the results are the difference between sustainable excellence and catastrophic burnout. Isn’t it strange that too much of anything good, like pleasure, deep work or runner’s high, can end up being the very things that destroy us?