On learning of the success of The Hobbit, and the possibility of the public desiring a second book about hobbits...
"At the moment I am suffering like Mr Baggins from a touch of 'staggerment', and I hope I am not taking myself too seriously. But I must confess that your letter has aroused in me a faint hope. I mean, I begin to wonder whether duty and desire may not (perhaps) in future go more closely together. I have spent nearly all the vacation-times of seventeen years examining, and doing things of that sort, driven by immediate financial necessity (mainly medical and educational). Writing stories in prose our verse had been stolen, often guiltily, from time already mortgaged, and has been broken and ineffective. I may perhaps now do what I much desire to do, and not fail of financial duty. Perhaps!"
I share a bit of this sentiment of Tolkien's. I think that every choice of mine regarding employment has been made in order to do what I desire to do, only to find out that it was not what I desired to do, and it became a job of necessity, working to pay the bills.
I no longer have much of a faint hope of doing what I desire to do.
In this I envy Tolkien.
Quotation from The Letters, #17, page 24