Common sense is in no way tied to education. And you don't have to be smart to get a degree, you need to have good learning/test taking skills. That said, some degrees are worth more than others, IMO.
My parents' expectations were that their children would do better in life than they did, and part of that was getting a better education (both have Bachelor's degrees). My expectation for my child is the same, that she would do better in life than both her parents, including her education (both of us have Master's, we both dropped out of our terminal degree programs). I can understand if academics is really not her thing and her passion lies elsewhere. And I will support her as long as she's being sensible about it (for instance, if she wants to major in dance, that's okay with me as long as she also majors in something that will get her a decent job that puts food on the table).
Gwenn, I really don't understand your sister's comments at all. It's *great* that you found employment in the area of your studies, and it's actually a field you find rewarding and fulfilling. Sour grapes, methinks.