* Emotional response to the performance: It's possible that Styles felt overwhelmed or emotional after the performance, and that this led to him crying. This could be because he felt a strong connection to the music, or because the performance held special significance for him.
* Physical exertion: Performing can be physically demanding, and it's possible that Styles was feeling tired or drained after the show. This could have contributed to his crying, as physical exhaustion can sometimes lead to emotional release.
* Fan interaction: Styles has a strong connection with his fans, and it's possible that something that happened during the performance, such as a particularly touching moment with a fan, may have caused him to cry.
* Personal issues: It's also possible that Styles was dealing with personal issues that were unrelated to the performance and that these emotions surfaced after the show.