Why was Bart and Lisa's relationship so suggestive?
that scene where they playfully tease each other then get told to get a room
that scene where Homer says "can you believe we're married to those dorks?" to Bart, in reference to Marge and Lisa
that episode where Bart and Lisa are implied to be a married couple in a mini-car
that time the writers joked about Bart and Lisa having a baby together and keeping it a draw when they shared a room
that episode where they become "best friends" and forfeit once in a lifetime opportunities just to spend an afternoon with each other
Lisa sleeps in Bart's bed after having a nightmare instead of going straight to her parents
countless hugs and kisses