When someone gives you a pep talk it is to build you up to help you accomplish something. In sports a coach might give a player a pep talk before the game to bolster his confidence. At work the boss might give you a pep talk to get you to do a better job.
Pros and cons are arguments for or against a particular issue. Pros are arguments which aim to promote the issue, while cons suggest points against it. The term has been in use since the 16th century and is a shortening of a Latin phrase, pro et contra, which means “for and against.” Considering the pros and cons of an issue is a very useful way to weigh the issue thoughtfully and reach an informed decision.