Knowing art?

Today in class we discussed the idea of sometimes knowing allot about art can be a good thing and sometimes it can be a bad thing. First off, when you know less about  art, you are more able to appreciate it. When you know less about the subject that you are examining you are

- less apt to critique it.

-appreciate if from the standpoint that you do not know as much about it.

-recognize the fact that it must have taken allot of effort to do this because it seems very difficult to you.

then again...

When someone knows more about art, they are more able to appreciate it because 

-the are more familiar with the subject area.

- and you know how difficult or easy something was to make so you can respect the artistic process.

Now a question i pose is, if you know allot about art, is it possible that you can never appreciate somebody's work of art because you expect greatness or perfect every time.