Discussion on answer by Thomas Markov: How does the Dimension Door spell interact with a mount summoned by the Find Steed or Find Greater Steed spells?

@Odo In fact, dimension door poses a clear exception to that rule in its description: "It can be a place you can see, one you can visualize, or one you can describe by stating distance and direction". It is clearly different from a spell like misty step which has a range of "self" and not "500 feet": the (primary) target of the spell dimension door is not the caster; it influences the caster, although that does not make it "its target".

@Odo Why is the range of DD 500 feet if it doesnt target something within 500 feet?