"How troublesome" (めんどくせー, mendokusē, English TV: What a drag) is Shikamaru Nara's catchphrase. Shikamaru purposefully uses this phrase to toss his point across that he's the type that would rather watch clouds all day than pick a fight, especially with a female opponent. This phrase is also used sometimes by Shikamaru's father, Shikaku Nara.
In proper Japanese, the phrase should be mendōkusai (面倒くさい, 面倒臭い). Shikamaru has a habit of slurring the word, saying it with "ē" instead of "ai".