Charles Darwin read Lyell's “Principles of Geology Volume 1” while he was travelling on the Beagle, and when he returned to England they became close friends. Darwin vents to Lyell in this letter from 1861.
As Robert Krulwich has noted, it’s nice to know geniuses had bad days like the rest of us. And it’s nice that they had friends to text correspond with when they did.
Happy Birthday Charles! And to the rest of you - Happy Darwin Day!