I've seen alot on here that people hate to see these episodes that aren't serious or have any character development. That makes me sad that people forgotten the true meaning of Adventure Time. Adventure Time is a adventure-fantasy, Not a complete anime drama or whatever. We will probably never know about Betty, The Mushroom War, Finn's Past,  PB's Past, or see another Lich story arc. Pen and his crew aren't like that, because if it was like that, the series would be terrible. Not to say that I like the character development episodes, I do. In fact, Simon and Marcy was one of my favorite episodes. So please don't say I only want comedy in the series. We get character development in most episodes, it is just a small amount to where we don't notice it. 

Adventure Time is about adventures, not drama.