I should have paid more attention in undergrad

If I had known when I was 20 that when I was (nearly) 29 I'd be looking at various academic papers and trying to determine if they were novel, would I have paid more attention? Or would I have just thought, I could rely on wikipedia (which is what I do).

So many of these concepts are vaguely familiar (principal compenent analysis, eigenvectors, support vector machines), but I feel like I never really understood them. I learned enough to regurgitate it to pass the test, then immediately repurposed those brain cells.

And now I'm left wiki-ing and scrounging the web for references, simple illustrations, something to get me to pass this current test.