The five-minute rule 

Whether you enjoy TV sci-fi or not, one's thing's for certain: You can always tell if an episode will be good or terrible after the first five minutes. That's because sci-fi shows have to pack the premise into the first act, and the premise is what makes the whole episode tick. 

Oh, so this episode is about Worf's son visiting him on the Enterprise and experiencing difficulty adjusting? Snooooooooze: BAD EPISODE. In another episode the entire crew's memory has been erased and they have to piece together what happened? Hooray: GOOD EPISODE. It's all right there in the first few minutes. 

With new shows like Fringe and others that try to maintain a storyline throughout the entire season this distinction is less clear, but that's also the reason that these shows aren't as immediately satisfying as Star Trek or X-Files: There was something nice about knowing that the central problem revealed in the first few minutes would be addressed in the last few. 

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