Photos are for remembering, if nothing else. There are many other reasons for taking photos also - but bringing back memories is the primary one for most of us to take photos.
I was looking for a certain photo today and came across this one - it is from our time in Hawaii and was taken on 1/1/12 about 6:15am at the Black Sand Beach on the big island. The 20 second exposure gives some star movement but also captures the purples in the sky...and the water becomes silky smooth. I remember this well.