1 To enjoy the view
While the sun is setting, a combination of colors flare up in the sky and make for a beautiful view, which some people like to watch.
2 It's relaxing
Watching the sunset can be a relaxing experience for some people, as the view is soothing and the colors appeal to their senses.
3 It's romantic
Some people find the sunset a romantic view and like to watch it with their loved ones or their partner. (See Why do some people love rainy and dark weather?)
4 It's a new page
The sunset metaphorically stands for the turning of a new page and the end of a day. Some people enjoy watching it to remind themselves that tomorrow is always a fresh start.
5 It improves the mood
It has been proven that watching the sunset relieves stress and can improve a person's mood.
6 Photographers enjoy taking pictures of it
The sunset is a great view for photographers who appreciate the beauty of the sky and its breathtaking colors during sunset.
7 It's inspiring
Some people find the sunset an inspiring experience that they wouldn't want to miss when they're in need for a little inspiration in their life. (See Why some people think that Will Smith is very inspiring?)
8 It looks majestic from a high point
Some people climb mountains and go hiking right before sunset so they can enjoy the view from an elevated place since it looks even more majestic from above.
9 They appreciate nature
People who appreciate nature and its wonders never miss a chance to watch the sunset.