Life is a little more fun when you know some Japanese, whether it's to communicate with nihonjin who can't use English or to catch the attention of cute coeds on campus. One word you can get quite a lot of mileage from is sugoi (sue-GO-ee), which means "amazing" or "incredible" and which can be used just about any time you need to express awesomeness. See a Japanese man who's adept at playing the Super Mario theme on an accordion? Just tell him sugoi! and your meaning will be instantly communicated. Then there's daijobu (die-JOE-boo), which means "okay" or "alright" and is generally one of the first words a person learns after arriving in Japan (well, after biiru o kudasai "please bring me a beer" anyway). Finally, the word naruhodo packs a lot of meaning into those four syllables, essentially expressing "I see" or "that's right" or "what a brilliant suggestion, you have changed my viewpoint 180 degrees."