It helps to get into him when young. First one I read was Have Spacesuit Will Travel, when I was about 9 or 10.
One book that pissed me off was a text book for a science fiction literature class.
Lots of great stories followed by a series of commentary and essay questions by Isaac Asimov. Bastard.
I'd read some really fascinating Robert Bloch or Ray Bradburry story delving into the human psyche when subjected to extremes and then Isaac would proceed to tell me what crap it is because the actual speed of Deimos, the first moon of Mars, is xxxmph, not yyymph which means none of the story could actually take place....
What really pisses me off though is crappy movie adaptations of great works of literature.