One subject that's always fascinated me has been the tendency of Japanese singers to mix English lyrics in with Japanese music, such as the OP (er, the opening theme) to "flying pantsu" anime Sora no Otoshimono (iTunes link here) in which the Japanese lyrics suddenly give way to English, "I can hear your heart bell, can you hear my heart bell?" This random use of "decoration English" for songs is by no means rare, and all manner of popular songs in Japan feature random phrases like "one more chance! never give up!" or "nice to meet you, good to see you!" or "un du trois!" (the latter is not even English, but no one here notices that). Supposedly this trend started with famous singer Yumi Matsutoya (iTunes link), who grew up near Yokota Air Base near Tokyo and was fluent in English since childhood. My own theory about why Japanese songs often feature English words and phrases in them is that the Japanese generally have a positive image of English, and it's possible to embed these "happy" emotions in songs in this way.
Japanese popular music often contains random bits of English for decoration.