This quick little gif demonstrates the difference between focal lengths and how they stretch or compress the sense of depth.
This animation was created with a zoom lens where the photographer started close to the object fully zoomed out and then he or she moved back, zooming in to keep the object the same size in the frame at all times. The frame where the background is farthest away is shot fully wide.
Not only is this a neat effect (Dolly Zoom) utilized in movies such as Vertigo but it also demonstrates how extreme spatial distortion can be. Perhaps contrary to “conventional wisdom” to create large distances between characters, move in and use a wider lens. To create a tighter and more claustrophobic framing, move away and use a higher power lens.