Musical Episode/Headscratchers

• I have to give props to Buffy the Vampire Slayer explaining why it was a musical episode (Scrubs too), but has anyone else ever sat through a musical wondering how the heck everyone breaks out into the same song and dance at once?
  • Everyone breaks out into dance and song in musicals because they are in a musical. It's their style. Buffy and Scrubs aren't musicals per default, so they must explain the style-change. Much like the fairytale episode of Scrubs where explained as being a Good Night story Dr. Cox told his son.
  • Of course, there are shows like Phineas and Ferb, wherein characters MUST burst into song at least Once an Episode and it more often than not gets no explanation and doesn't make sense in-universe, but generally people just kind of accept it.
    • I guess you could also do that with a generally non-musical series having a musical episode: they don't really have to explain why it's happening, most people would probably accept "okay guys we're a musical this week for the LOLS."
  • On an episode of Family Matters with a musical number it's because it's All Just a Dream. Making for one of the few semi-justifiable uses of that trope ever ( the finale of Newhart being an even rarer example of a full justification), because how many ways are there to make sense of a sudden musical number erupting out of nowhere?
• What about the musical episode of X-Play, where Morgan and Adam created the 'ultimate hybrid' video game... and it turned out to be a monster (both the game and the episode)? Perhaps a bit of layered symbolism into the idea that Morgan and Adam don't know what makes a good game?