is brand loyalty stupid? Cognitive dissonance.

I shoot Nikon DSLR but I also have canon S95 which I bought few months ago. But now I have constant desire to rid of the S95 and get the Nikon P7100 even though deep down in my heart I know the S95 is a better camera for me.

The the reason that I want to change is because I have this desire to have all my camera gear Nikon. I know this is very stupid, we should buy whatever tool for our situation and reward the company that makes the better product.

I searched up on this issue and came across this term cognitive dissonance.
http://en.wikipedia.org/wiki/Cognitive_dissonance

I wonder if you have the same, do you stick just to one brand even though there are better camera out there, or do you have different brands of camera.