Lapis wasn't "annoying," Peridot was. Lapis was a total dick, you mean. She was being extremely hypocritical, too--if she had known Steven came up with the ideas, she would have liked them. But since they involved Peridot, they were automatically garbage to her. Peridot was being way too nice to her in response, but then again Peridot's probably just lonely.
Actually, I loved this characterization of Lapis! She was way too much of an innocent victim in the last episode, to the point where it seemed like she was just lying. I want her to be more villainous and cruel.