ACCURACY VS ARTISTRY
Conventional wisdom would seem to dictate that when adding a sound effect to a scene you would want it to be as photo real as possible. Depending on the scale and style of the film this may well be true, but in many cases an accurate sound effect does not serve the needs of the story.
Case in point, I was working on a noir-ish scene set in a dingy basement where our anti-hero was giving a soul-less monologue to a tied up bad guy. At the end he points his gun at the villain and pulls the trigger... blackout. I started with an actual recording of a .45 but in the context of the story it just felt anemic. This gunshot wasn't just a gunshot but the sound of our hero's last vestige of humanity winking out of existence. It was the sound of the villain's horrible deeds finally catching up with him.
I ended up EQ'ing more bottom end into the effect as well as adding a touch of delay/reverb and finally layering a 12 gauge shotgun blast under the whole thing. The director joked to me about how he flinched every time he got to that part of that scene.
In short, don't just think literally when adding a sound effect. Think about what the sound effect actually represents in the overall story.