I discussed this with a sci-fi loving friend once, and we realised that our preferences actually had little to do with the trappings of dragons vs robots!
The heart of Sci-Fi, he said, isn't actually about the future -- it's about now. It's about using the future to explore where we are right now, or even to explore our past -- capturing the optimism of a past decade and imagining where it could have taken us instead, for example. Look at something like Star Trek's original series, which used "new life and new civilisations" to explore the societal problems our world was dealing with at the time of the series. The sci-fi that feels the most like sci-fi explores societies, contrasting our ideals with a hypothetical new society, or following our ideals to their logical conclusion and pondering what kind of society they'll create.
I decided that I liked Fantasy because I wanted to write about people. But the important part of a person, to me, isn't that she grew up in Chicago and works for the local paper; it's the things she's insecure about, the ways she copes with those insecurities, the things she wants, the ways she sabotages herself and the ways she is strong -- there is so much in the unique deepness of a person that I want to explore without having to know every detail of growing up in Chicago in a specific time period. And all of those details get in the way sometimes; your experiences and your biases colour how you interpret people from a specific place or in a specific situation.
So I write fantasy -- it's like clearing that slate. You have no biases and no experiences about riding dragons or learning fire magic or growing up in Fantasylandia, and so you can get to meet and know and explore this person deeply without anything getting in the way.
That's not to say Fantasy doesn't have societies and Sci-Fi doesn't have deep characterisation -- often they do! But I think the two genres do having leanings that make them good spaces to focus on those things, if that's what you want to focus on.