In television, mediocrity finds a way to survive. Time and time again, the TV world has proven that innovative, clever sitcoms will typically fail while the perfectly ordinary ones will thrive. They're the cockroaches of TV, practically indestructible.

Take, for instance, Rules of Engagement on CBS which, according to The Hollywood Reporter, has been renewed for a sixth season. I have nothing against the show and I'm sure there are plenty of people who enjoy it (it's averaged over 8 million viewers per episode this season). But from its generic title to its cast of former wacky sitcom sidekicks (Just Shoot Me's David Spade and Seinfeld's Patrick Warburton), it's not likely to be topping critics' lists or winning a ton of Emmys any time soon.

The show's continued success despite very little excitement or pop culture buzz is nothing new. Mediocre sitcoms like Rules of Engagement have a proven track record of outlasting better ones.

On ABC, According to Jim and George Lopez both lasted more than 100 episodes, with According to Jim going on for eight seasons with 182 episodes. That's two more episodes than Seinfeld had, which might be the most depressing statistic in the history of the universe.

Meanwhile, underrated ABC gems like Better Off Ted, Samantha Who? and Sons and Daughters were quickly canceled. If you have no idea what Sons and Daughters was, seek it out, because it was every bit as brilliant as Modern Family. And now solid ABC comedies like Mr. Sunshine and Happy Endings are in serious danger of early deaths.

FOX let Til Death run for four seasons and 81 episodes, crushing the survival of the Emmy-winning Arrested Development. And now FOX has quickly canceled Traffic Light and Breaking In following the death of Running Wilde.

Being ordinary is better than being good when it comes to sitcoms, although there are exceptions to the rule (Modern Family, The Office and The Big Bang Theory). But for Rules of Engagement, it's good to be a harmless, generic sitcom that no one really notices but which continues to get a solid amount of viewers. It might not be the best, but it's lasted a lot longer than most shows. Ironically, the mediocre comedies get the last laugh.

(Image courtesy of CBS)