Kirk is a speed demon. He likes the ship to leave fire trails out of space dock because maneuvering thrusters are for pansies. He barks orders and Scotty gives him that concerned look with comments like, "I din'na think she can handle the stress, Cap'n!" So naturally, the Enterprise would somehow be tuned for aggressive impulse power baselines.

We all accept that when you're at warp, stars fly by. When you're on impulse power, you're sublight and stars are more or less static due to relative differences in speed between the two. I think scientists all over agree on this principle.

Then why is it that in many episodes or movies the stars are just flying by when the ship is still in first gear? This is hard to tell through static screenshots, but take the example in "The Wrath Of Kahn" below. Here we see the Reliant and Enterprise pretty much at point-blank range. They're slowly passing each other. They're at impulse. Yet when you watch the playback, the stars are passing by in the background:

Oh sure, it looks cool, but in the back of my head the BS meter is going off. In "Obsession" during the chase of the gaseous cloud, Kirk orders to move in slowly at "sublight one-quarter speed." In the following moments, the Enterprise fires off some torpedoes ... but it's obvious in watching the background during playback that the Enterprise is apparently at warp. Either someone on the bridge isn't following orders or someone in the effects department screwed up:

In "The Doomsday Machine," big bad Commodore Decker takes over the Enterprise and pursues an attack course against the planet killer, a.k.a. the huge hollow log in space with fire burning inside. In the screenshot here, they're practically on top of each other. The Enterprise is going right, the planet killer is presumably going left. One would conclude that combat at these distances while roaming around each other like this would require impulse speeds ... yet the stars in the background are racing by like there's no tomorrow:

In "Balance Of Terror," Scotty claims that the Romulan warbird's power is "simple impulse." It's a little hard to believe because the Enterprise and the warbird are running around each other as the stars pass by at warp speed. Make up your minds, folks:

When Kirk and crew were transporting the Dohlman in "Elaan Of Troyius," a Klingon ship is discovered at a distance which soon matches Enterprise's sublight speed. In this shot, the Klingon ship is supposed to be pacing on a parallel course, yet in playback the shot clearly shows the Klingons in warp. The shot of the Enterprise previously immediate to this one has the stars at standstill.

There are plenty of other examples in the series, but these should wet your appetite. Conclusion: someone in continuity work failed to maintain the consistency or didn't understand the difference between impulse and warp speeds.

Fired.