Answer to Question 1
People are more likely to use the indirect method in cases where it is more difficult to trivialize (i.e., when the dissonance involves serious attitude/behavior conflicts). (Obviously, what follows is idiosyncratic.) Were I to be impatient with someone, I'm most likely to remind myself that I am generally not an impatient person, and I know I get that way when I'm under stress. I resolve to address directly the things that are causing me stress, that I'm not naturally a stressed-out hurried personthis resolution helps a lot to reduce the dissonance.
Answer to Question 2
Most people think that prosocial behavior and aggression are polar opposites, but these two areas overlap more often than people think. First, consider the motivation underlying aggression. If it is one intended to help the recipientfor example, a coach acting sternly to motivate an athletethen that aggression is a form of prosocial behavior. Secondly, consider the specific action of an instance of aggression. If it inflicts pain but it is intended to benefit the recipient in some wayfor example, a tattoo artist applying a needle to one who has requested a tattoothen it is closer to prosocial behavior than it is to the generally negative view of aggression. Finally, consider the effects of aggression. Generally, people assume that aggression produces harm to the recipient, but that is not always the case. A surgeon may amputate a person's limb, which could be viewed as an aggressive action, but the effect of this action is to benefit the recipient rather than harm the recipient.