Alison Arngrim and Melissa Gilbert were good friends real-life. They used to play territory wars on the set.
I hate that Nellie Oleson!
Caroline: Laura! Don't say "hate" - don't even think "hate"! I'm sure Nellie has her good qualities somewhere.
Charles: Your ma's right, half-pint. Now on the way home, we'll try and think of some!
In some episodes, when Caroline moves the right way, one can see that she is wearing a bra. The series is set in the 1870s to the 1880s, and bras were not invented until 1912.