For me Science Fiction means any narrative or story set in a world at a higher technological stage than us.
It's disappointing that the common definition of science fiction has degenerated so much. In classic science fiction the technology or science plays a central role in the story; it's not just part of the backdrop. If you can take the story and, without losing the central theme, re-write it in an alternate setting without the science and tech aspects then it's not real science fiction.
Philip K. Dick's 'Minorty Report' and Issac Asimov's 'I Robot' are good examples of classic science fiction. The story requires the technology. OTOH, Star Wars and most episodes of Star Trek (varies by series) are, imo, examples of stories which should not rightly be called science fiction since they could easily be rewritten in another setting and still retain the core themes and plot points.
Time-sharing is the junk-mail part of the computer business. -- H.R.J. Grosch (attributed)