Minerva may present as a quiet and reserved women, but at the same time she can be outspoken. I think it is more just that she knows when to speak and use her voice, but also how to separate her personal life from her teaching life. I agree that the students of Hogwarts are like her children; especially her Gryffindors.
Truth be told, before we found out that Dumbledore was gay, I always thought that she would be a good match for him

Seriously though - they are both intelligent and excel in transfiguration, love Hogwarts, etc. They would have made a cute couple... *sigh*
Okay, I'm corny, I know... you can all say it now.