The final score doesn't always tell the full story. I'll give some examples.

Penn State vs Ohio State 2006: Score was 28-6 OSU, but PSU led 3-0 at halftime, OSU answered with a TD and a nearly intercepted TD where Smith threw the football away to avoid a sack, and PSU had to settle for a field goal due to a penalty. In the final 2 minutes, PSU throws two pick sixes. The entire game was close, but people think it was a blowout. This was more like the 17-10 PSU vs Michigan game where both teams kept pace with each other and neither team could move the ball.

PSU vs OSU 2005: Final score was 17-10 PSU, but despite what many think it honestly wasn't that close. OSU couldn't move the ball, and was lucky that Troy Smith found an opening for their lone TD. OSU's best drive was the field goal. Penn State had another scoring opportunity but decided to run out the clock at the end. On the field, Penn State was as dominating over Ohio State as USC was over Michigan in the 2007 Rose Bowl.
Florida vs Michigan 2008 Capital One Bowl: Michigan was leading 28-14 at one point and had the game in the bag, but a couple turnovers allowed Florida to think it was still in the game. Michigan had full control of the game through the entire game.

Penn State vs Illinois 2005: Ok, people know it was a blowout due to the 63-10 score, but they asked when compared to OSU's 40-2 performance "You gave up 10 to them?". Truth is, Penn State led 56-3 at halftime, and felt sorry for them so PSU took a knee for the entire second half (only other TD was a kickoff return) and very literally allowed a meaningless Illini TD in the final 2 minutes because it was their homecoming and they didn't want Zook to feel entirely disgraced. It could have easily been a 112-3 thumping.
Machine Gun Man: Not true, how they performed on the field gives an indication on how they'll match up against other, similar teams. If the 2006 Ohio State game really were a blowout, I don't think they'd have played Michigan down to the wire, thumped Tennessee, and beaten Michigan State.
Machine Gun Man and those who think the score means everything: Alright, one more example. In 2006, Michigan was completely thumping Ball State and led 31-12 at one point. Michigan's mistake was bringing in the second stringers too early. The final score of 34-26 doesn't reflect on the game at all. Do you really think because Michigan brought out the reserves too early that Ball State was almost as good as Michigan and possibly belonged in a BCS bowl? On the field, Michigan's closest games were Penn State and Ohio State. The Rose Bowl was honestly closer than the Ball State game.

To everyone else: I understand that all that matters is the W or the L, but how the game was played on the field gives an indication of how good a team is every bit as much as the score. That explained why unranked Penn State who was 8-4 managed to thump 9-3 Tennessee who was ranked #18.

I love the 2007 PSU vs Wisconsin example, it shows perfectly how momentum can let a game get out of hand, PSU won 38-7