7. The Breakfast Club 2
The entire point of The Breakfast Club is that the children head out into the world following their long stint in detention unsure of whether what happened that day actually changed anything at all; have they broken down the social barriers constricting them, or will they simply all return to their own cliques and never speak again? It's part of the thought-provoking genius of John Hughes' 80s teen masterpiece, something that would have been completely undermined by a needless sequel, set 10 years after the original film. Hughes at least had the smarts to want to wait a decade to make it - so as to avoid garish aging make-up - though by this point, his already uneasy relationship with Judd Nelson (who Hughes nearly fired from the original film) had soured sufficiently that it just wasn't going to happen.