Trust your gut instinct the most when it tells you not to do something.
If your intuition is to work with person X, maybe it's right, maybe it's not. But if your intuition is not to work with a particular person, you should probably heed it.
Positive intuitions are more easily corrupted by biases such as wishful thinking.
For example, when assessing a potential hire, you may be sexually attracted to the person. This is going to positively affect how you view the person and may contribute to a positive hunch on the person's qualifications, even if you consciously know your desire to have sex with her/him shouldn't affect your decision.
On the other hand, if you're not sexually attracted to the candidate, you're not going to have a negative intuition on the person. It's neutral — a non-issue. Any negative hunch you do have is probably going to be grounded in something meaningful or relevant.
Bottom Line: Listen to your gut in the negative more than in the affirmative.
Related Post: Asking Questions in the Negative: What Do You Regret? How Did You Fail? There is a penetrating quality to negative framing.
(The above insight comes from Auren Hoffman.)