There were twenty-four dream interpreters in Jerusalem, and if you brought the same dream to all of them, you would get twenty-four different answers. According to Berakhot 56a, every one of those interpretations would be fulfilled—because a dream follows its interpretation.
The Talmud dramatizes this principle through the story of Bar Haddaya, a professional dream interpreter with a simple business model: pay him, and he would interpret your dream favorably. Refuse to pay, and the interpretation would be catastrophic.
Abaye and Rava came to Bar Haddaya with identical dreams. Abaye paid. Rava did not. The same verse—(Deuteronomy 28:31), "Your ox shall be slain before your eyes and you shall not eat thereof"—was read to both in their dream. To Abaye, Bar Haddaya said: your business will profit so much that the joy will steal your appetite. To Rava: your business will fail and grief will make eating impossible.
Another shared dream cited (Deuteronomy 28:41): "You shall beget sons and daughters, but they shall not be yours." For Abaye: your children will be so numerous that your daughters will marry outside the family, and it will feel as though they were taken captive. For Rava: your wife will die, and another woman will raise your children.
The passage also preserves a remarkable exchange between Rabbi Yehoshua ben Hananya and the Roman emperor. The emperor challenged him: "You Jews claim to be wise—tell me what I will dream tonight." Rabbi Yehoshua said: "You will see the Persians capture you and force you to herd unclean animals with a golden staff." The emperor thought about it all day. That night, he dreamed exactly that. The line between prediction and suggestion had collapsed entirely.