Well, Sasuke's sad story starts with his family's tragedy. His entire clan was wiped out. This left him an orphan at a young age. He was left with only the goal of vengeance. He had to leave his village, Konoha, and train with Orochimaru, who was not a good influence. Sasuke's journey was full of darkness and self - doubt as he was constantly haunted by the past and his need for revenge. He lost his innocence and had to face many tough battles alone, which was really sad.
In some fanfictions, there are scenes where Sakura is in danger and Sasuke realizes just how much she means to him. For example, if Sakura is injured while protecting Sasuke, Sasuke's reaction of guilt and his newfound determination to always be by her side can be an extremely emotional part of the story.
Many fanfictions show Sasuke's sadness through his flashbacks. He constantly relives the day his clan was massacred, and these memories haunt him. Writers often use these flashbacks to highlight his internal pain, which affects his relationship with Sakura as he sometimes pushes her away because of it.
The key element is the massacre of his family. It's the starting point of his sadness. Another is his separation from his friends in Konoha. And his pursuit of revenge which consumed him.
In a'sad Sasuke love story', perhaps it could be about Sasuke falling in love with someone but being unable to fully embrace that love because of his past traumas and the burdens he carries. His love might be doomed from the start as he is constantly pulled between his emotions and his quest for power and revenge. For example, he might push away the person he loves in order to protect them from his enemies or his own dark side.
One great Sasuke and Sakura sad love story fanfiction is 'The Unreachable Love'. In this story, Sasuke is constantly torn between his quest for revenge and his feelings for Sakura. Sakura, on the other hand, tries her best to hold on to their relationship but is constantly pushed away. It's really heart - wrenching as you see her hopes slowly fading away while Sasuke is consumed by his dark path.
In many of these fanfictions, a big theme is the power of time. Time can either heal the wounds of their love or make them worse. For example, as time passes, Sakura might grow more bitter about Sasuke's actions. Another commonality is the theme of hope. Despite all the sadness, Sakura often holds on to a glimmer of hope that Sasuke will come back to her. And of course, the theme of loss is prevalent. The loss of their relationship as it could have been, the loss of the happy future they might have had together.
It can show how Sakura's shyness affects her interactions with Sasuke. For example, she might blush and stammer when near him, which Sasuke may initially misinterpret. Her sadness could come from Sasuke's lack of response. As the story progresses, Sasuke could start to understand her better and their relationship could grow from there.
A great 'shy and sad sakura x sasuke fanfiction' might be the one where Sakura is shy about her love for Sasuke which has been unrequited for a long time. This makes her sad. However, after a dangerous mission where Sakura saves Sasuke's life, Sasuke starts to see her in a new light and they begin to build a connection.