I think it was in Doctor No there was a conversation between Q, M and Bond. Bond's favourite weapon was the Beretta, and Q explained their downsides. Bond was ordered to use the Walther (IIRC) as a replacement. It was in a box. At the end of the scene, Bond picks up the box, surreptitiously hiding the Beretta underneath. As he is about to walk out, M, continuing with his writing and without looking up, says to Bond, "Oh and Bond, leave the Beretta behind on your way out." (Or something like that).
It's a small scene, but it tells you a lot about the characters. It just adds to storytelling, even though it isn't a key scene.
Another example is the difference between the original Robocop and the remake. In the original, the villain Boddicker is hailed into the police station. Battered and bruised, he spits blood on some paperwork on a desk and says "Just give me my fucking phone call."
How badass is that? The villains in the remake were much less interesting, and it made for a weaker movie. I guess modern screenwriters /could/ write decent if they wanted to, but I assume that gunning for a 13 certificate really neuters the possibilities. I also suspect that there is more influence by the producers, who insist that certain things need to be in certain ways "for the demographics". So what you end up with is a story that's bent to suit the demographics, rather than just telling a good story.