Personally, I think people shouldn't brag about their horses because their horse isn't the best first off and unless your the best, why brag? And even if you are the best, why brag? It's obnoxious.
Because to them, their horse is the best horse. I know mine is. 8) Bragging, depending on how it's done, is about being proud and sharing. Bragging to be snarky and snobbish isn't. Most people can tell the difference.