1. Autistic people: Autistic people may have social barriers, and it is difficult to understand and adapt to social occasions, and may not be suitable for making friends actively.
2. Patients with mental disorders: Patients with mental disorders may be emotionally unstable and behave strangely because of illness, making it difficult to establish stable friendship.
3. Extremely introverted people: Extremely introverted people may find it difficult to make friends on their own initiative because of their lack of self-confidence and fear of socializing.
4. Paranoid patients: Paranoid patients may find it difficult to establish a stable friendship relationship because of their suspicion and distrust of others.
5. Arrogant people: Arrogant people may be unwilling to accept other people's opinions because of their high self-esteem, so it is difficult to establish equal and healthy friendship.
6. Malicious and unfriendly people: Malicious and unfriendly people may find it difficult to establish sincere and respectful friendship because of selfishness and deception.
In short, people who are not suitable for making friends may be autistic, mentally retarded, extremely introverted, paranoid, arrogant, malicious and inhuman. These people may not be able to establish healthy, equal and sincere friendship for various reasons. However, this does not mean that these people are not worthy of attention and care. We should respect everyone's differences, understand and tolerate their characteristics and difficulties.