I loved that conflict and I always thought one of the main issues between them was the fact that they were too similar. They both had very dominant (and sometimes somewhat childish) personalities. They both wanted things their way. Whenever we encountered someone from Emily and Richard's world they were always commenting about how similar Lorelai was to her mother, or commenting on Emily's "wicked" streak. I think the main difference was Emily did everything exactly the way she was supposed to based on the world she grew up in. I think that's part of what bothered Emily so much. She sees herself in Lorelai and can't understand why Lorelai can't fit into their world when she was able to. I always felt Rory's similarities to Lorelai were superficial which was why they got along so well. Rory was quiet and studious and more willing to take a backseat to Lorelai's more boisterous personality.