Certain traits are commonly shared by people viewed as being bad managers.
10 most common traits of a bad manager:
(1) does not communicate clear expectations
(2) plays favorites
(3) does not show concern for employee personal/career development
(4) bad mouths people behind their backs
(5) does not provide feedback
(6) needs to prove that s/he is always right
(7) is not self-aware (and is blind to own failings)
(8) betrays trust
(9) does not listen to others
(10) puts his/her needs first
Additional traits:
(1) arrogant
(2) makes ill-advised decisions
(3) needs to control all decisions
(4) cannot allow anyone else to look good
(5) cannot tolerate being contradicted