Who will be happiest in heaven?

If all we are truly trying to do is get to Heaven, then why bicker over branches of Christianity? Are there different levels of happiness in Heaven? Even though we will all be perfectly happy, will the people who did more of the correct things during their life be more perfectly happy in Heaven? Will there be a huge difference between the people who thought that Mary was holy and those who believed she was a normal human? Will those who didn’t eat meat on certain days be happier than those who did?