Editors tell me my dialogue passages are too long, but I’m only telling it the way it is in real life. What’s wrong?

Beginning Writer's Answer Bookedited by Jane Friedman

You’re probably doing too much in the way of “telling it the way it is in real life.” You must refine your dialogue so that you present the reader with only the essence of reality. Conversation in real life is never as pointed as writers present it in fictional dialogue. Readers will be bored by dialogue that recounts the polite rituals and trite conversations that are a part of everyday life. Compress and focus your dialogue so that your characters get right to the point when they talk. All dialogue should either advance the plot, characterize the people, or both. If it doesn’t do these things, it’s not effective or necessary.