Different exposures can make many images look different.
The term Perfect Exposure is often tossed about in photography. This is a highly debated topic because the notion of 'perfect exposure' varies from photographer to photographer. What is a perfect exposure for someone might be an under-exposure for others and over-exposure for the rest. The thing is, perfect exposure is all in the eyes of the photographer and his / her imagination and the way s/he wants to treat the subject. The thing about photography is that if you set free several photographers at a scene none of them will come back with the exact same composition. That is even though the light is the same as well as the elements are the same in the construction. Each photographer will see it differently and produce a different image. Let's take an example.
Let's imagine that you have a street scene with a mix of potential subjects that can be highlighted in a composition. A photographer could intentionally under-expose the scene (meter for the highlights) and capture a silhouette of the subject. That would probably also serve the purpose of diluting everything else in the scene and just focusing on getting a silhouetted view of the subject. And to top it all s/he may even choose to post-process the images in monochrome.
Another photographer may choose to expose for the subject but also bring into relevance the background and the foreground. S/he may choose to use a small aperture, therefore, bringing the whole of the scene into focus. S/he may also use center-weighted metering instead of using Spot metering and therefore the subject (considering that it is in the center of the frame), would be highlighted mostly but the rest of the scene will be slightly underexposed but still be discernible in the image.
The thing is the same scene can be treated differently by different photographers and therefore each photographer would come up with a different definition and therefore image of the scene.