I can't seem to make up my mind, Simba or Sarabi...agree with what others have said on why. While I think Timon, Pumbaa and the
"Hakuna Matata" motto would help Simba as a distraction, emotional pain is deep and doesn't heal easily...and that sort of guilt is especially heavy. You can have a smile on your face while on the inside you're on the verge of a breakdown. I think this is why the scene in 1/2 where Simba comes to T&P saying he "had a bad dream" really struck me as having a
much deeper meaning. I think it's safe to assume what Simba's "bad dream" was about.

I also feel very bad for Sarabi...and would have loved to see more of the pridelands during Scar's reign (I got so upset when they went with
"The Morning Report" as the song to work into the movie, instead of the epic
"Shadowlands", which would have added so much to the plot, and to Nala's character)!
For me it's between Sarabi or Simba, but I feel bad for all of the characters on the list, they each suffered in their own way. I even feel bad for Scar and I have my reasons for that, which I'm sure would just open a whole new debate.
