Some actors just don't cut it

Some actors make their characters unpleasant and despicable on purpose. Some actors, however, just do too good a job of it. They give the impression that fiction is too close to truth. A good example is Carl Ballantine's portrayal of Lester Gruber on the TV series McHale's Navy. Character and actor just seem to be someone I would not like to have known. Maybe it was merely a good job of acting,  but I doubt it.