There should be a class in everyone's senior year that teaches basic life-things like etiquette, doing taxes, how a mortgage works, and how to prepare for a job interview. It should have tests to evaluate the students' understanding, but it shouldn't impact their GPA.

Edit: It seems a lot of people are saying this is a parent's job and I don't want to keep responding with the same thing so here:

You aren't wrong. But that doesn't mean that this idea would be wrong either.

There are plenty of kids whose parents do not have this wealth of knowledge to share with them. Parents who aren't from this country, parents in poorer cities who are ignorant or work too much to have time for this, parents who became parents at an age before they had the chance to learn these things, and there are children who don't even have parents (thanks to /u/PromptedHawk for adding this last example).

Do the children of these types of parents not deserve this information just because their parents didn't/couldn't teach it to them? Does the real-world education of a child stop where their parent's did?

Stop looking at the world through the scope of your own life and situation. Think of others.