1. Privacy protection: Some people want to keep a certain degree of privacy on the Internet, and don't easily add strangers as friends to avoid revealing personal information.

2. Criteria for making friends: Everyone has their own criteria for making friends. Some people feel that information or chat methods do not meet the criteria, so they are unwilling to add friends.

3. Social anxiety: Some people are anxious about socializing and don't want to expand their interpersonal relationships too much.