Well...

Pathos is arguably the most effective rhetorical device out there. If you can appeal to the emotions of people, you can more successfully accomplish your goal. Turn on the t.v. See the lil fuzzy panda locked up in the tiny cage screaming '(fill in your name here) SAVE ME!!'? That, my friend, is an appeal to pathos.

Think of all the historically significant speeches you can come up with. (Yes, that is plural, hopefully there is more than one, and no, Steve Jobs' presentations don't count.) They all use pathos. Take Martin Luther King Jr's famous 'I Have a Dream' speech. He used pathos, he employed it and worked it to the bone, and the response was overwhelming.

If someone's emotions become tangled up in an argument, more likely than not the emotions will win out over their brain. Look at it this way. Are you more likely to get more money for your birfday if you tell your grandparents, 'oh no, I don't need anything,' or if you tell them, 'mom and dad never let me do ANYTHING fun and I've been doing homework four hours a day for the past 10 years!' Nine times out of ten, or if your grandma happens to be Suze Orman, the latter is going to get you more money. With that in mind, Lamags, I've been working on stuff for your class for hours straight for weeks now, and I could really use a break to continue with my charity work....