The linked sources don't say the four "came to me before you", as above, but rather "came before you". So it's a joke about the fickleness of dream interpretati

The linked sources don't say the four "came to me before you", as above, but rather "came before you". So it's a joke about the fickleness of dream interpretations. That is, a dream of driving a four horse chariot is taken by one interpreter as bestowing the speed of horses on the dreamer, while the next interpreter says oh no, it's a dream about having four in front of you!