There is something that does not exactly sit right with Adams's description of virtue as something that we should admire. (p. 19) Adams states that virtue could be partially described as perspectives in thinking about what kind of person "we would want to be."
I do not believe this is a reliable method of identifying moral virtue. People are capable of admiring the wrong things, and often do: someone might admire the promiscuous accomplishments of his friend, or his capacity while binge drinking, though these behaviors are clearly not virtuous.
People are also capable of scorning what would normally be considered virtuous (or at any rate, moral) actions, and again, they often do: One can hate another's honesty and initiative when the results mean he will learn the unpleasant truth: if this were not the case the scenario of "shooting the messenger" would not exist.
Adams, fortunately, does not make this the central or even an overall important factor for determining a moral virtue; it is more supplementary than anything else. Though it is ideal that one admires what is good and scorns what is bad, this is not always the case. Thus, this method is not a reliable one for determining moral virtue simply due to the fact that people are fallible.