One possible reason is the pressure of always having to be perfect. As a virtual idol, Miku is expected to look and perform flawlessly all the time. Any glitch or mistake could be seen as a failure, which might make her sad.
One reason could be the difference in their destinies. Silver is often tied to the future of his own world, while Blaze has her own duties in her dimension. This can lead to a sense of separation and sadness. For example, if Silver has to go back to his time to fix things and Blaze can't leave her world, it's a sad situation.
One possible reason could be the loss of a loved one, like in the case where the cat's owner died. Another might be separation from friends or family, as the cat that lost its mouse friend. Or neglect, such as when the family focused on the new baby instead of the cat.
One reason could be neglect. If the owner doesn't take proper care, like not feeding it enough or not providing shelter, the horse would be sad.
Another reason could be unrequited love. As I mentioned before, if Meowth has feelings for another but is rejected, that's very painful. It can lead to a long - lasting sadness.
Financial difficulties might also play a part. If they were in debt or lost all their savings due to some unforeseen circumstances, it could have caused a great deal of stress and sadness. Their relationships might have suffered as a result, and this could be the sad story of Jamich.
One reason could be abandonment. Maybe its owner didn't want it anymore and left it in the junkyard. Another is lack of proper care. In the junkyard, there's no one to give it regular meals or medical attention. Also, the environment is harsh. The dog has to deal with all kinds of dangerous and dirty things.
Illness could also be a factor. Just like in real life, if the dog in The Sims gets sick and there's no proper treatment or care, it can lead to a sad story. The dog would be weak and suffering, and its quality of life would deteriorate.
One reason could be misunderstandings. For example, the boy might misunderstand the girl's intentions and say something hurtful, leading to a rift between them.
One reason could be poor management. If the management in a hotel or restaurant is disorganized, things like overbooking or slow service can happen. Another reason is lack of proper training for the staff. For example, if waiters are not trained well, they may not know how to handle customers properly.
One reason could be bullying at school. Other kids might pick on him because he's different in some way, like being too shy or having an unusual hobby. This can make him feel really sad and isolated.