Data was incapable of emotions.
Over the years, the android had learned to accept this simple fact.
And yet, he craved them nonetheless.
He caught himself wondering what it would be like to feel affection towards his friends. How it would be like to share their emotions, to laugh with them. How it would be like to experience 'love'. And, he wondered, what it would be like to 'dislike' something, or someone. How it would feel like to be 'nervous' or 'scared'. What it would be like to feel loss, and to 'grieve' it with the people he held close.
He would gladly risk feeling bad at times if it also meant he could not only understand, but feel love and affection.

But, in the end, these were nothing more than curiosities he may never be able to satisfy.

However, there was that other craving he had noticed - one that might be truly within his reach.

Despite being an android, Data seemed to have a reoccurring desire for...family. He had explored this desire in the past, with the construction of his beloved daughter. But his satisfaction was short-lived, when he noticed that he had lacked the ability to shed even a single tear over the loss of his child.
His desire for family had no emotional context, he concluded.

But even then, it persisted.

And so it came that sometimes, seemingly at random, he thought of his brother.
He would think of the time they had found him sitting on a distant shelf, abandoned and forgotten. And he thought of the moment after his successful reassembly, when they had first looked at each other. If Data had to give his thoughts back then a name, it would be 'hope'. He had hoped that his brother, Lore, might just be like him. That he would not have to be alone anymore, that he had...family.

Data wondered briefly if, despite all the unethical, horrible things Lore had done, and his own incapability to feel,

he missed his brother.

It should be impossible, he thought, yet it lingered in his mind for days, weeks.
He remembered the words Doctor Crusher had said the very same day his brother ripped his dream away from him:

"They're brothers, Data. Brothers forgive."

And his father's words looped in his head, then:

"Lore is far from the maniacal android you have made him out to be."

Data swelled on these words. Perhaps, he wondered, there was a way for things to be different.

Perhaps things could change.

Data had spent the last few days lingering on what seemed to be a feeling of desire - the desire to have family; the desire to have the brother he always wanted.

His growing determination to find a way for Lore to be the brother he so desperately seemed to grave led him to spend his free time standing in front of a distant shelf, staring at his estranged sibling. Lore sat there, disassembled, lonely, as he had so many years ago before Data had found him.

As the android stood there, day for day, he tried so desperately to make sense of the other; to make sense of why he did the things he did, of why he seemed so very bitter.

Counselor Troi had once told Data about good and evil.
"There is no pure good or pure evil in this world, Data," she had explained to him. "Humans are neither entirely good nor entirely evil. It is motives and ideology that drive us. Our upbringing and our experiences are what shape our view of the world. It is what makes us humans human."

Data did not understand her reasoning. He had concluded that it was impossible for an emotionless being to understand.

But Lore was different. He had emotions. Perhaps, Data thought, his brother was a lot more human than the android would ever admit to be.
And perhaps the way Lore saw the world could change, just like a human's could.

And so it came that his hours of standing in front of a shelf turned into analyzing his brother's data banks; his memories, his knowledge, his perception of past experiences.

Many hours did Data spend sitting at a desk, studying Lore in secrecy; eyes fixated on the computer, and his brother's head sitting in front of him.

If Data had emotions, he would feel as if the other was judging him.
It was a rather curious, yet illogical thought.