I've interviewed two people with a complete flat affect, one convicted felon (our standards are higher now), several people who were dismissed from MD schools, and several more who were dismissed from UG for cheating. One guy had had someone else take an exam for him.
While I didn't interview these types, we've rejected some people for being "scary".
The wise
@gyngyn has reported of one applicant who had a single digit MCAT score. No, not single digits in each category...but for the entire exam!
He also had one person who applied to literally every MD school in the US!