For us, it really does matter. My husband is 6'4". For us to sleep in a double bed, it is *very* uncomfortable. We've had to when staying with relatives. The added size of the Queen doesn't give us extra room, it gives us just enough with his long legs. We sleep on a King at home because it's more comfortable than a Queen. The King does give us extra room, which I gladly claim as mine. If we can request or book a King when we're at WDW or elsewhere, I do my best to get one, even if I have to pay more. So to answer your question - for us, it isn't just a mental thing.