If the best surprises are the ones that come out of nowhere, I don't understand why everyone gets so upset when I cut their brake lines.

Professionally, almost all my big surprises are good. Once in a while I go into a theater expecting big things from a director or cast, only to see them whap me in face with a wet Nerf bat for two hours, but for the most part I'm caught off guard by the stuff I felt certain would suck — yet, through hard word, sorcery or satanic bargain, didn't.

-- Local show times, theaters, trailer.

The thorn to that rose is when you're pleasantly surprised, it's easy to mistake "better than expected" for "legitimately awesome." Many's the night I've stayed up bandaging my wrists after handing out an extraneous +. I'm running that risk again with the should-have-been-terrible Knight and Day, but what can I say, it entertained the bejesus out of me.

Cameron Diaz is charmed when she bumps into Tom Cruise at an airport, but she's a little put off after he gets attacked by and kills everyone on their flight, including the pilots. The next day she's picked up by men posing as federal agents — men who Cruise warned her might try to kill her.

When things go south, he rescues her. Cruise is possibly a bad guy, and he definitely stole something from the U.S. government, but he's the only person who can stop Diaz from being killed.

The basic tenets of being cool require me to hate Tom Cruise, and generally I'm happy to oblige. (Not that I need any help being cool; you should see my elf costume.) The fact I kind of liked Cruise in Knight and Day is almost as preposterous as the movie itself.

I say "preposterous" with impressed, surprised approval. The scene where Diaz flirts away in the middle of a plane filled with people she doesn't realize are dead — that is some seriously insane, seriously funny shit. Pulling off a scene like that should be as impossible as not strangling that stupid barking dog who lives in the apartment below you, but director James Mangold underplays it enough for its inherent ridiculousness to shine.

That's Knight and Day in a nutshell: it sometimes plays as a black parody of the spy/action genre but mostly plays as a funny, high-energy spy/action thing. In some ways, the upcoming comparison is just wrong, but tonally, the movie's not that far off from Shaun of the Dead and Hot Fuzz.

Of course, the whole thing could have been ruined if Cruise had overacted it, and man, there is more room for ham in his role than in the National Bacon Silo and its gift shop. His non-manic approach will evoke sighs of relief from audiences everywhere.

Diaz, on the other hand, does some screeching. If you could see my face, it would be a frown.

There's not a whole lot of that, however, and whenever there is, you can anticipate a quick jump back to comic action. First-time screenwriter Patrick O'Neill's script isn't flawless (not all the dialogue works as well as it wants to), but it's clever, offbeat and stuffed with conceptual absurdity. Diaz's attraction to Cruise works much better than it should, in part because she clearly doesn't understand it that well herself.

Really, the only reason Knight and Day isn't flat-out great is its third act can't sustain its wild pace. The story resolves well enough, it just seems to stick around a little too long. Despite that, Mangold maintains his tonal mastery of semi-satire, and what the hell, I'm even down with the romance.

Going in, I expected this would have a whelk's chance in a supernova of being any good, but you know what? I think it'll surprise you, too.

Grade: B