Especially with regards to politics, I argue to find things like common ground or hear a new perspective. I generally like hearing alternatives to my own ideas, or being able to further solidify my own views or try to convince others. The most frustrating part is that arguments are made so much about "winning" that it doesn't become a discussion about finding the truth, both sides fail to concede anything to the other, and instead compete to see who has better endurance to sticking with their own point of view even when it doesn't necessarily make sense.