Complex sentence: By the end of filming, Eastwood had finally had enough of Leone's perfectionist directorial traits, who, often forcefully, insisted on shooting scenes from many different angles, paying attention to the most minute of details, which would often exhaust the actors.
Split into simpler sentences: By the end of filming, Eastwood had finally had enough of Leone's perfectionist directorial traits. Leone, often forcefully, insisted on shooting scenes from many different angles, paying attention to the most minute of details, which would often exhaust the actors.