I'll give it a shot...
First, you can try to remind players about the place in the world their PCs inhabit. If they're at low level, remind them about what's new to their characters, and that a sweeping vista isn't something they can teleport past yet.
The PCs might be in a rush because you gave them a mission, while the players may be in a rush because of time restraints in the real world, or they might just be eager to get to your next encounter. I'd take either form of engagement with your game as a compliment.
You might be surprised at what an individual player might think of a description... it doesn't have to take forever for it to have an impact.
As an example, here are two different descriptions of a door:
-You turn the corner see that your trail leads up a 30 percent incline before ending 300 feet away. Before you is a door, made of gold metal, 50 feet tall and 30 feet wide, with 10 foot hinges. It is open, and you approach.
-You turn the corner to see a full view of the mountain you've been glimpsing through the trees for some time. Far ahead of you, an immense golden door is set into the mountainside, towering over you even at this distance. The door stands open, admitting wagons like yours that look like toys by comparison.
Of course, then you have to come to terms with the fact that not only are they only going to want to hear that once, but that that's how it works in the real world too. Familiarity breeds contempt, and all that.
So, my advice is (without knowing any more specifics about your situation):
1: Remind your players about what constitutes cool for people in their PCs' position and history.
2: Time your cool moments for when everyone has time for it.
3: Use comparisons instead of hard numbers, at least at first.