Complex sentence: Brandon is annoyed by Sissy's visit as she is emotionally needy, which he has no patience with, while also cramping his style, interfering and hindering his personal life, which forces him to think about the increasingly unhealthy obsessive path his life is taking.
Split into simpler sentences: Brandon is annoyed by Sissy's visit as she is emotionally needy, a trait with which he has no patience. She is also interfering with and hindering his personal life, which forces him to think about the increasingly unhealthy obsessive path his life is taking.