In Percy Jackson fanfiction, the 'crazy trouble with love' could be things like unrequited love between demigods. For example, a character might fall in love with another who is sworn to a different quest or allegiance, creating a lot of emotional turmoil.
One way love causes trouble is through secrecy. If a character has to hide their love for someone because of the potential reactions from others in the camp, it can lead to a lot of stress. For example, if a demigod from one cabin falls in love with someone from a rival cabin, they might be afraid to show their feelings publicly, which can create internal conflict and also cause issues with their friends who might sense something is off. Also, love can make characters act irrationally. They might put themselves in danger to protect their loved one without thinking about the consequences, which could put the whole group at risk during their adventures.
Well, it could be that Peter falls in love with someone he shouldn't, like a villain's daughter perhaps. This would lead to all sorts of crazy trouble as his friends and the city he protects might not accept it.
Most likely Ben would be one of the main characters. Since it's a Ben 10 fanfiction, he's usually at the center of things. And if it's about love, perhaps his love interest, whoever that may be in this story, would also be a main character. Maybe Gwen could also play an important role, either as a friend giving advice or getting involved in some way in the love - related drama.
Well, it could be about all kinds of crazy things that happen when love is involved in the Ben 10 universe. Maybe it's about a character falling in love with an alien they meet during their adventures. Or perhaps it's about the troubles that come with having a relationship while also being a hero and having to deal with all the alien threats.
Perhaps Peter realizes that his superhero responsibilities are more important at the moment and decides to put his love life on hold. By focusing on being a hero, he might find that the 'crazy trouble with love' slowly fades away as he has less time to get into relationship drama.
One common theme is miscommunication. Ash often misunderstands the feelings of others or vice versa, which leads to all sorts of trouble in the love department.
Develop your characters' emotions deeply. Since it's about 'love' and 'crazy trouble', show how the characters grow and change because of their relationships. Use vivid descriptions to bring out the Avatar setting. For example, describe how the air temple looks when the two lovers meet there during a storm, which represents the 'crazy trouble' they are in. Also, don't be afraid to introduce new elements that fit within the Avatar universe.
Gray could also be a part of it. He might be the one teasing Natsu about his love problems or even getting involved in some sort of love triangle situation with Natsu. And Erza, she could be the voice of reason, trying to get Natsu to sort out his feelings in a more proper way, while also dealing with her own reactions to Natsu's love - crazed antics.
In some fanfictions, Ichigo's love might make him act irrationally. If he's in love with a character who is in danger, he might take extreme risks to save her. This not only puts his own life at stake but also can disrupt the balance between the living world and the Soul Society. For example, he could recklessly enter a dangerous realm without proper preparation just to rescue his love interest.