She was not unhappy, she was only not happy.

At first it was a speechless delight to have as many novels as she pleased, and she thought Tom the very prince of bounty in not merely permitting her to read them, but bringing them to her, one after the other, sometimes two at once, in spendthrift profusion.

The first thing that made her aware she was not quite happy was the discovery that novels were losing their charm, that they were not sufficient to make her day pass, that they were only dessert, and she had no dinner.

When it came to difficulty in going on with a new one long enough to get interested in it, she sighed heavily, and began to think that perhaps life was rather a dreary thing--at least considerably diluted with the unsatisfactory.

How many of my readers feel the same! How few of them will recognize that the state of things would indeed be desperate were it otherwise! How many would go on and on being only butterflies, but for life's dismay! And who would choose to be a butterfly, even if life and summer and the flowers were to last for ever! "I would," I fancy this and that reader saying.
"Then," I answer, "the only argument you are equal to, is the fact that life nor summer nor the flowers do last for ever." "I suppose I am made a butterfly," do you say?
"seeing I prefer to be one." "Ah! do you say so, indeed?
Then you begin to excuse yourself, and what does that mean?
It means that you are no butterfly, for a butterfly--no, nor an angel in heaven--could never begin excusing the law of its existence.