Complex sentence: Danny's eccentric friend and coworker, who also happens to have a crush on him, she lived with Marianna in her freshman year at college and has hated her since, because she was the coat rack at all of the parties.
Split into simpler sentences: Danny's eccentric friend and coworker, who also happens to have a crush on him. She lived with Marianna in her freshman year at college and has hated her since, because she was the coat rack at all of the parties.