久念成病久思成灾
[jiŭ niàn chéng bìng jiŭ sī chéng zāi]
'Long-term Longing Causes Disease; Prolonged Thinking Leads to Disaster' expresses the idea that long-standing obsession leads to trouble or calamity. This user is probably warning others against excessive longing or obsession that might hurt both the admirer and their loved ones.