Every man — and by man I mean people, not the male gender — has at least one emotional trigger which takes him out of his comfort zone. That one button, when pressed the right way, brings out a different side of her that she does her best to not show.
Finding that button on a person — or the challenges of finding that button — shows you what a person is made of, how much they can be pushed. This is important insight to have, especially for a person you’re friends with or going to be working with or may have to one day depend on.
I’m not saying to go searching for the button on people — you may not be ready for the response — but be alert to when and where the signs may show.