1. The theme does not meet the requirements: If the theme of your paper does not meet the theme of a journal or conference, it is likely to be returned. Before submitting your paper, you should read and understand the submission guidelines carefully to ensure that the topic of your paper meets their requirements.

2. The research method is unclear or unreasonable: If your research method is unclear or unreasonable, the reviewers may think that your paper lacks scientificity, so they will return it.

3. Paper structure is chaotic: If your paper structure is chaotic and there is no clear introduction, method, result and discussion part, then the reviewer may think that your paper lacks logic, so it will be returned.

4. Insufficient data or inaccurate analysis: If the data in your paper is insufficient or inaccurate, the reviewer may think that your paper is unconvincing and therefore return it.

5. Poor writing quality: If there are a lot of grammatical errors, spelling errors or formatting errors in your paper, the reviewers may think that your paper is of poor writing quality, so they will return it.

6. Plagiarism or plagiarism: If your paper is plagiarized or plagiarized, the reviewer will definitely return it. Before submitting your paper, you should make sure that your paper is original and not plagiarized or plagiarized from other people's works.

7. Insufficient references or improper citations: If your paper has insufficient references or improper citations, the reviewers may think that your paper lacks academic nature, so it will be returned.

8. Papers do not meet the format requirements of journals or conferences: each journal or conference has its own format requirements. If your paper doesn't meet these requirements, it is likely to be returned. Before submitting your paper, you should read and understand the submission guidelines carefully to ensure that your paper meets their format requirements.