Well, actually, there are plenty of examples in the books, where Dumbledore is excessively humble.I wouldn't say that Dumbledore was humble. Not arrogant but he knows he's a genius and he is not ashamed to say it.
I know! When I read that, um, toned down version of the tales written by Mrs Bloxam, and saw the word "huggled" being used, I immediately thought of the Hugglepuffs....Also the word huggle is used. I thought it was a Mugglenet thing - I was wrong.