As a rule of thumb I won't hire someone I wouldn't want to actually work with day to day.
Other than that, it depends on the balance, the person's awareness to his faults and his willingness to improve. Everything can be improved and it's often for the benefit of both the company and the person, so if he/she is willing to actively work on it (and of course if they are good enough in other areas so it's worth the investment) then it's enough to at least give it a try.