Just because I thought of it the other day. For many years, this was taped above my computer monitor. It is often cited, but out of context, as a John Muir quote, which it is, but as remembered by Sam Hall Young and quoted in his book about Muir. I give the section, with my beloved quote in bold.
For a bit broader context - After his adventure years wandering the Sierra Nevada as a young man, Muir married and took over his wife's family's farm. Being Muir, he worked 16-18 hours a day and was driving himself into poor health. His wife was starting to worry, as were friends. In the meantime, though, he amassed a reasonable amount of his savings, his wife finally prevailed. She told him his contribution to the world would be writing, speaking and organizing, not growing apples. The money he made in the fruit business gave him the platform to become the writer and organizer and happy person we know as John Muir. This was near the low ebb of that period.
A very brief visit at Muir's home near Martinez, California, in the spring of 1883 found him at what he frankly said was very distasteful work—managing a large fruit ranch. He was doing the work well and making his orchards pay large dividends; but his heart was in the hills and woods. Eagerly he questioned me of my travels and of the "progress" of the glaciers and woods of Alaska. Beyond a few short mountain trips he had seen nothing for two years of his beloved wilds.
Passionately he voiced his discontent: "I am losing the precious days. I am degenerating into a machine for making money. I am learning nothing in this trivial world of men. I must break away and get out into the mountains to learn the news."
It's one of my two favorite JM quotes.