When you've carefully checked all of the facts and your attitudes and still find that there's just something about your supervisor that's causing the problem in your relationship you should suspect?

You should suspect that the issue may stem from interpersonal dynamics rather than objective facts. It could be a matter of differing communication styles, values, or expectations that aren't aligning. Additionally, personal biases or unresolved conflicts may be influencing your perception, making it essential to reflect on your feelings and consider open communication to address the underlying issues.