Here's what The Situationist had to say:
To appear warm people convey themselves as less competent, and to appear competent people convey themselves as less warm, according to a recent study conducted by a team of researchers in the psychology department.
Here's more from Prevention.com:
No one wants to be the woman everyone hates at work—you know her; the one who never ends an email with "thank you" and who pretends she hasn't met you even though you've met. Six times. But according to a new study from Princeton University, your efforts to be nice (and not be that woman) could be shooting your career in the foot.