Obsessive fans, also known as 'stans' (a portmanteau of the words 'STALKER' and 'FAN'), are individuals who are extremely passionate about a particular celebrity, musician, or other public figure. They often go to great lengths to show their support, such as attending concerts, buying merchandise, and engaging in online conversations about the person they admire. Obsessive fans can be both positive and negative, as their enthusiasm can lead to both constructive and destructive behavior.