I don't believe this is correct. I'd suggest you stay away from this kind of answer. The last thing you want it someone to reject you because they think you can be argumentative. Never talk about weaknesses, but if you have to, make it as inconsequential as you can -- don't mention how you can be argumentative and not be aware of your surroundings.

Rather, stroke the ego of the person you're talking to. I grew up always knowing I wanted to do <whatever>. In high school I started learning as much as I could from the library and it really started to grow my interest as I read more and more. This school is particularly high on my list because I know you have some of the best professors and a culture that focuses on the students in a way that bigger universities cant.

That is assuming you're going to a small school. I imagine big schools don't have time to interview every single student that wants to apply.

This answer talks about you, your interest in whatever you're going to study, and why you think the school is awesome.