When you photograph something symmetrical, it is best to either stand right in the center of the subject to underscore the sense of balance and graphic design, or you should stand significantly off-center to shoot. Don't stand slightly off-center or else it will look like a mistake.
The picture of the ceiling in St. Fin Barre's Cathedral in Cork, Ireland, above, is an example. The reason why the symmetry looks correct in this photo is because I set up my tripod precisely in the middle of the church.
By contrast, I took another picture of the interior from the side of the church (see image below), and you can see that this angle, also, is valid. What would not be good is if I shot the ceiling from two or three or four feet off-center. Both of these images were done with HDR and I processed them slightly differently to get different color, but the principle I'm talking about here is how to correctly emphasize symmetry.
Note: Jim Zuckerman is a top stock photographer who teaches for BetterPhoto's online photography school and photographer certification program. Among Jim's courses are Developing Your Creative Artistic Vision and Eight Steps to More Dramatic Photography.