I often find that some photos become favorites more for sentimental reasons than for aesthetic considerations. This photo is perhaps the best example I have of that. Pictured is the Mission Creek area near the Little Bend of the Missouri River. I have spent the night in my sailboat, Ariel, which is named after a sea spirit in Shakespeare's play The Tempest. I have walked up on to a bluff and am looking northeast over a glass-smooth body of water.
Is this a great photo? No. Is is one of my favorites? Yes. But only because it helps me remember what it's like to be in (for me) the perfect place: warm, quiet and utterly peaceful.
Incidentally, I use this photo to illustrate the rule of thirds and the principle that the eye is typically drawn to the brightest part of the picture, which is my sailboat.
No photo info: this is a scan of a film image (so 20th century!)