Watch The Background !
Have you ever seen horns growing from your grandmothers head in a photograph? Don’t worry, it’s just an optical illusion so she’s not gone over to the “dark side”.
But there’s a good reason for the horns. The human brain scans the scene and focus on what it finds interesting and eliminates the rest. This is all done subconsciously so you won’t even notice it. The camera can’t however selectively filter out information like your brain can, so you end up with everything that was in the view finder, not just what you thought you saw.
Your eyes also see the scene in three dimensions but the camera can only render the same scene in two dimensions. The result is that tree branches seems to grow from your grandmothers head and lamp poles from your house. Always look for and try to
this kind of problem, especially in portraits where they can be very distracting and certainly not very pleasing.
Distracting Background
Above is an example of a portrait having this problem. The tree seems to grow from my wife’s head (believe me, it’s just an illusion 
