Bulverism: Should we make an argument rationally or personally?

To be honest, the first time I read this article, I didn't get the main idea. But after I read this several times, even though I’m still not sure if I am right, Lewis seems to try to show how to make an argument. The problem is, should we take an argument personally, or rationally?
Well, I would say that people can make the argument in either way depend on the situation. In my opinion, I prefer (that is also what I usually do) to argue personally. For our girls, sometimes, when we went out shopping, we all liked to discuss the style of clothes tirelessly. When one of us wanted to buy a shirt, she would always ask others’ opinion. Is the shirt looking good or bad? At this point, since everyone has a unique body, the shirt may fit someone perfectly and looks ugly on others. For example, since I am skinny, I like to wear tight shirt. For some of my friends who is little bit heavier, they may rather like to wear a loosely shirt. If I argue personally, I don’t want my friends to buy a loosely shirt as I didn’t like the style. But if I think about it rationally, I would suggest them to get the shirt since it fitted on them better.
So sometimes, when we make an argument, you’d better stand on someone else’s position and think in their way.
I’ll still use buying clothes as an example. When people buying clothes, they can not only consider the quality and style but also the price. Can you be able to afford the clothes? As a friend, I know their economic situation. Even though the shirt looks good on them, by thinking rationally, I won’t recommend them not to buy it if they are almost run out of money.
Like what I said, people has better to make argument in either way depend on the situation. However, since God creates everyone as to have a unique mind, I would always like to argue with others personally. Maybe it sounds selfish, but if everyone judges every case rationally, can human being still have argument with each other? If everyone takes every case objectively, there will be no argument: like what Lewis said, “it was supposed that if a thing seemed obviously true to a hundred men, then it was probably true in fact.” In other words (according to my understanding), if people don’t have their personal opinion toward something, instead, they just follow what other people said and thought, the “something” will became a fact since no one bother to think about it based on their own situation. Nonetheless, since God creates us, and gives us the gifts of creativity and ability to think and argue. Why do we waste them? When we make an argument, it’s better to put ourselves inside the argument and think about it by our mind but by the fact.