one thing that you might cover is that harry conveys the idea of teh wizarding world being rather gullible to daphne. they are very prone to believing everything they are told without even teh barest semblence of thinking about it.
also, they seem very prone to, at least to me, acting very quickly and impulsively to things. you coudl even use teh bouts with dumbledore and the fallout from rita skeeter as examples.