Umbridge's Detention.

[Charis]

i think Harry not telling anyone was maybe not the best thing, but i completely sympathize with him and couldn't imagine harry doing anything else. i think partly it was his pride but it wasn't really the bad kind of pride. i mean, think about if he did tell someone. what could they do about it? umbridge basically was in charge at the school, so DD couldn't really have helped Harry. it mightve been good for future refrence or smthing but i dont think anything could ahve been done abt it. Like Harry said, it was b/w him and umbridge and he didnt want to give her the satisfaction of knowing she got to him. to harry, telling someone about umbridge would have meant admitting defeat.

[Mint]

Well, perhaps he couldn't do anything else - but Im glad to know that I was not the only one who was irritated with him.

[Athena Appleton]

One thing to keep in mind is the constant similarities between this Wizards War and Hitler's Germany in WWII. The bad guys are going to use lots of psychological warfare, and this is one example of it. Harry didn't tell on Umbridge because 1.) he didn't think there was anyone he could tell, 2.) he didn't want to give Umbridge the satisfaction of knowing she was getting to him. Some would call it pride, but it just shows that Harry is not going to be an easy case to crack.

[Phaerie]

If any of you have studyied psychology, then you'll know that people will quite happily do terrible things because people tell them to. (kinda like the imperius curse)

This also works when people are told to do things to themselves. there are lots of factors involved in making the person comply, without telling someone in authority. ( after all how many people who are bullied at school because they are too scared or worried about what might happen)

harry wouldn't tell on Umbridge (so to speak) partially because he fears what will happen, he doesn't want to risk getting any members of the OotP into trouble, nor does he want to get expelled from hogwarts.
Secondly hes a moody 15 yr old, whos way too proud, it would severely dent his own sense of importance to admit that he needed help.

However one would have thought that somebody who had suffered Umbridges detention would have said something, maybe the quill has a charm on it which encourages you not to tell anybody?

[Athena Appleton]

Nah, the only people who we know of that have to suffer through that particular detention was Harry and Lee... both were Gryffendors, both were hotshots... I really think that they both felt that the best way of defying Umbridge was to not go to the authorities and show they were upset by it.