You should always interview in a busy public environment to keep your interviewee alert.

Interviewing in a busy public environment is generally not recommended for customer persona development. Such settings introduce distractions and noise, making it difficult for the interviewee to concentrate and provide thoughtful, detailed responses. It can also make them uncomfortable discussing personal or sensitive information. A quiet, private setting, whether in person or virtual, is preferable as it fosters a more relaxed atmosphere, encourages open communication, and allows for better focus from both the interviewer and interviewee, leading to richer, more accurate insights for your persona.