After several long weeks without a decent new release I was thrilled at the prospect of seeing “127 Hours,” the new film from Oscar-winning director Danny Boyle. Unfortunately, the Topeka theaters did not seem to share my enthusiasm, because “127 Hours” was not shown in any of them this weekend. So, I went and saw “Due Date” instead.

For a long time my instincts have been to avoid cross-country or road trip movies because the vast majority of them are awful. However, both Robert Downey Jr. and Zach Galifianakis have been fairly reliable for the past couple of years, so I decided to give “Due Date” a shot.

If I was not being paid to write a review for it, I probably would have walked out within half an hour after the opening credits. I would not call the movie terrible, exactly, but the phrase ‘painfully predictable’ seemed to keep popping into my head uncontrollably. If I find myself sitting through a bad movie I can usually stomach it because its ending, while the general conclusion is obvious, the specifics of how that conclusion is reached are usually cloudy enough to keep me in a limp state of suspense, but this ending was just so damn obvious that I felt insulted as a viewer.

Yes, good casting and an overabundance of shock and disgust manage to earn “Due Date” quite a few laughs, but as pretentious and finicky as it sounds, a good comedy is about more than a bunch of cheap gags. Sure, there are many exceptions, but this film is not one of them. The plot begins to fall apart beneath even the mildest scrutiny, but in no way is this done intentionally. The film just expects you to accept that the pair can go what would have to be over 200 miles off course to get gas, that stealing a government vehicle while causing millions in damages will not make the authorities pursue you for longer than five minutes before letting you keep it, and that shooting someone with a stolen gun in a stolen truck while stoned will have no legal repercussions or even stop you from guest starring in a sitcom within the year.

Virtually everything bad that happens to the two characters in the movie is patently contrived and utterly outside the realm of plausibility. The toxicity of both characters is so potent that the film constantly has to insert melodramatic moments of emotional vulnerability in an attempt to reinforce the absurd notion that, after all that these guys do to one another, they would actually be friends.

“Due Date” was kind of amusing, but completely and totally needless. Even by Hollywood standards.