Chuck is a strange show with a curious but lovable collection of stories and tones. Josh Schwartz created it after The O.C. went off air. It’s strange to think that the creator of a teen drama would then jump to a spy comedy, but his chracter-based sensibility is what actually makes the show such a delight.

The show kicks off as a underachieving Stanford drop-out named Chuck Bartowski finds himself with a computer database of government secrets called “The Intersect” stored in the unconscious of his brain. The original database is destroyed, so Chuck holds in his brain thousands of records on secret agents and secret villains. He’s teamed with a CIA handler, Sarah, as well as an NSA agent, Casey.

Meanwhile, Chuck has to keep his spy life secret from his family and friends and keep working at “Buy More,” a Best Buy-style store where he works on the “Nerd Herd,” solving computer problems.

The show tells a story in each of those three spheres — spy life, home life, work life — in most episodes, and they occasionally intertwine in hilarious (often unbelievable) ways.

The spy stuff is the most troublesome part of the show; it requires a lot of hand-waving, and the action sequences are usually cheaply produced. Still, the writers do a good job of capturing a feeling of danger — it gives the show some good conflict as its backbone.

The first season of the show deals with Chuck becoming The Intersect and his first adjustments to that. He unsurprisingly falls for the beautiful Sarah and butts heads with the gruff Casey.

It’s a fun but uneven show until about the halfway point of that first, thirteen-episode season. As we learn more about Chuck’s past at Stanford, and Sarah’s relationship to Chuck’s ex-best friend Bryce, the characters begin to connect.

Similarly, the side characters required some calibration. Chuck’s best friend Morgan, in particular, is annoying early in the show, and Chuck’s goofy coworkers do little to contribute to the show at first.

But by the end of that first season, the show was crackling. The writers gave more depth to the characters and started building some excellent serial conflict. A great arc of Chuck “breaking up” with his fake girlfriend to date sandwich-maker Lou (played by Rachel Bilson) added some variety to Chuck constantly pining for Sarah.

The conclusion to the first season was good, but it would have been hard to predict how quickly the show would ascend to great. I’ll defend the second season of Chuck to anyone. It’s full of so many good stories. A few highlights are: the return of Bryce and Chuck’s ex-girlfriend Jill, the mystery identity of “Orion,” a band of evil agents named “Fulcrum” closing in on Chuck, and, of course, Chuck and Sarah’s spiraling towards each other.

But more than just the good stories, the jokes got funnier, the characters became richer and more complicated, and a raucous sense of fun just pervades the show.

The best episode of Chuck is the penultimate episode of the second season, “Chuck Versus the Colonel,” in which Chuck and Sarah are on the run, and several worlds come colliding together. For people to sit through a season and half of slow boil character development with little change to the status quo, it was an unexpected potboiler that blows everything up.

The season finale is nearly as good, too. It sends Chuck’s best season out with a great plot twist (“Guys… I know kung fu”), and gives us a bittersweet turn in the Chuck-Sarah saga.

So the third season had some high expectations to live to, and the result was a mixed bag. The show eventually reverted to something of a status quo, with Chuck and Sarah not together but still thinking of each other. There was a major backlash against the show at this point, and it’s somewhat reasonable.

But it’s far from the atrocity fans made it out to be. I actually enjoyed Kristin Kreuk and thought her three-episode appearance should have been closer to ten episodes. The writers should have either gone big on the Chuck-dates-non-agents theme, or just abandoned it, so its brevity was frustrating.

The addition of Shaw (Brandon Routh, aka Superman) as a counterpoint to Chuck and romantic interest for Sarah was controversial — people REALLY wanted Sarah and Chuck to just get together already — but I actually thought he added a lot to the show, even though he started out pretty bland. His rise and fall was a pretty compelling side plot for the front half of Season 3.

Beyond the central romance, and the general frustration with the stasis, the show operated at a pretty high level. The show turned in some classics that season — I’d rank “Chuck Versus the Beard” just behind “Chuck Versus the Colonel” — and culminated in a great midseason finale where Sarah and Chuck get together for real, as well as a great true finale. Morgan is hilarious as an addition to the spy team.

Fatigue was starting to set in, though, and I have to confess: I didn’t keep up with the show after its third season. I stopped watching not because I stopped liking the show, or because I didn’t care what came next (like with Lost, for example), but just because it became inconvenient to watch it when I ran out of DVDs, and it wasn’t quite addictive enough for me to find a way to watch.

I also resented the direction of making Chuck a sort of spy hero of destiny as opposed to a likeable everyman making the best of a bad situation. Chuck was such a likeable character at the beginning because his crazy, ridiculous situation seemed to bring out the best in him.

If I ever finish off the last two seasons, I’ll write some addendum here, but this is all I have to go on.

What Chuck really comes down to is its treatment of characters and relationships. This is Josh Schwartz’s natural habitat, and it’s refreshing to see such a great calibration of comedy, drama, conflict, and character development.

The cast is uniformly solid, with Zachary Levi serving as the glue for the show as the title character. It’s a little bit unbelievable just how charming he is given the way his character is defined (a loser in a dead-end job), but the show goes to great lengths to make Chuck a great and complex character.

Sarah is also a great character. Yvonne Strahovski plays her well, and does an especially good job with Sarah’s professionalism lapsing into emotion now and again. Her standoff with Chuck as a romantic partner went on too long, but the dynamite chemistry with Zach Levi made it worth the long wait.

Adam Baldwin went from straight man to some mild comic relief as Casey, Sarah Lancaster is perfect as Ellie, and even Joshua Gomez grew on me. Frankly, you can go actor by actor, and there’s not really a weak link here.

Chuck is one of those shows that thrives on ENTERTAINMENT in a big, goofy, fun way — without ever skimping on the characters. It makes for a satisfying show, and I’d recommend the skeptics to give it a shot (but don’t give up before Season 2, when it gets good).

A couple of notes:

• This is ranked above fellow Schwartz show The OC as I’ve seen it deeper into the series, but I have to say The OC has a decent shot at overtaking this once I get around to watching past the first season.
• Jeffster! as a fake cover band made up with Chuck’s coworkers is one of my all-time favorite fake bands.
• Tough to say whether Casey’s wordless grunt of Captain Awesome’s “Awesome” or Sarah/Casey’s “Stay in the car!” is the show’s best catch-phrase.