Do you remember a year ago?

Maybe you've tried to forget the unmitigated disaster that was the 2012 Chiefs. Understandable. But it's instructive for what we'll talk about here, so please indulge me for a few paragraphs.

I remember a year ago. An 81-year-old woman called to say she had better luck getting to the bathroom on time than Matt Cassel did of completing passes. A 32-year-old man helped organize a major fan revolt and said it felt as if he were having a nasty and public fight with his girlfriend.

Stories like this popped up everywhere, and the message was fairly consistent: We're Chiefs fans. We don't ask for much. We just want a competitive team that appreciates us.

Today, the Chiefs are 8-0. The NFL's last undefeated team. Best defense in the league.

John Dorsey, their new general manager, sometimes hops on calls with season-ticket holders to thank them. Andy Reid, their new head coach, usually begins his news conferences after home games by praising the crowd - you can feel the ground shake.

And yet, some fans aren't happy: The offense stinks. The schedule's been easy. They've played against too many backup quarterbacks.

"I don't want to be that guy," says Pat Carson, a Chiefs fan in the Northland. "But we almost lost to the Browns at home. Case Keenum was great against us. And now we've got three games against Peyton Manning and Andrew Luck."

Even fans who are pleased with the Chiefs' 8-0 start may not find themselves quite as happy as they would've guessed a year ago.

Turns out there is a perfectly good explanation for this, one that is hard-wired into all of us.

Daniel Wann is a psychology professor at Murray State. His research focuses on sports fans, in particular. As it happens, he is also a die-hard Royals and Chiefs fan - enough that he did a playful tomahawk-chop chant when he returned my phone call.

He might be the world's best expert to not only confirm this phenomenon but also help explain it.

"What you're saying points to a lot of things," he says.

A long history of research in psychology shows that people - not just sports fans - overestimate how good they will feel about a positive outcome. This is just how we are. It's in our nature.

We can dream about something, and be happy when we get it, but quickly want something more. Job promotions bring extra stress, new cars grow old, big houses need to be cleaned.

This causes all sorts of conflicting emotions for sports fans.

"The euphoria is not quite as good as you expect," Wann says. "It's like, 'I thought I would feel really, really, really good. But I only feel really good.' So there must be some other issues. It must be because they haven't beaten anybody good."

Wann and Christian End, a psychology professor at Xavier who has also studied sports fans, each brought up the example of lottery winners. Studies and anecdotal evidence have shown that even big winners often don't end up happier than they were before.

There are some rough edges in comparing lottery winners to Chiefs fans, of course, but the point is that human nature makes many of us greedy and unsatisfied even with good results that we've anticipated and hoped for.

Wann says this particular reaction is especially true for fans of teams that haven't had much "true, top-shelf success."

I didn't have to ask whether Chiefs fans, going on 20 years without a playoff win, would qualify.

Some of this is in the way we anticipate. We tend to focus solely on the outcome, forgetting that even if the Chiefs are 8-0, our kid may still have colic or the government might still shut down.

And some of it is in the details we don't think about during the anticipation. Eight-and-oh is perfect in the abstract, but in an NFL stacked for parity, being unbeaten (or not) can depend on Dez Bryant dropping a pass or three opponents giving away possessions on punt returns.

"Your expectations are always changing," End says. "As we reach a certain space, our expectations are dynamic and always ahead a bit."

Back before 8-0 and thoughts about challenging the Broncos and talk of playoff seeding, the Chiefs were just a team coming off a rotten year that beat the Jaguars in their season opener.

You remember, right? Nobody knew quite what to expect from the Chiefs, but at least after a blowout win on the road we could be relatively certain this season would be an improvement from the year before.

Justin Houston dominated that first game. He would be chosen AFC defensive player of the week after recording three sacks and five tackles. In the locker room after the game, Tamba Hali screamed at his friend and teammate.

"C'mon, 50! You're leaving me behind already?"

Hali had a big smile on his face. He took the losing hard. Winning felt so good, Jaguars or not.

"Hey," he announced, "I'll give him all the sacks as long as we're winning."

Hali looked back over at Houston and laughed. This notion of dynamic satisfaction and expectations resides in all of us - fans wanting more wins and pass rushers wanting more sacks.

"At least for a few weeks," he said. "Then I'll want the sacks, too."

Hali laughed again. He was joking. Mostly.