I notice cool stuff after I pull a photo up on a monitor later, but it's ultimately your composition skills that did it either on purpose or not while lining up the shot.
Coolest thing I've ever got lucky with was a tilt shift shot where I lined everything up using a tripod then didn't look through the view finder when I hit the shutter release.
Got home and was going through the shots and noticed a bird somehow ended up in the narrow area of focus.