A Personal complaint about Statements

For the past 15 minutes I've been sitting at my computer trying to write a personal statement. I've googled 'Journalism Personal Statement', I've read through some of my friends' applications and I've even (albeit eventually) tried to write my own. But, nothing. I find it so easy to write whatever comes into my head, unfortunately in the current day and age this won't get my into my University of choice. Apparently nor will sending off a short message saying "please take me in, please, please, I promise I'll work hard, I'm quite intelligent I promise!" (not that I'd consider that anyway..hmm).
Bribery, begging, pleading.. none of these methods will get me into uni. The only method it seems is actually just writing the statement.
My biggest problem I think is having nothing to talk about. Us Brits are brought up to play down our successes and focus on our bad parts. All well and good for modesty but absolute rubbish for when it comes to selling ourselves. It's the same with CVs and Cover Letters. There is a thin line between selling yourself and showing off and so far no one seems to have sat comfortably on that line.
I remember going to Turkey a few years ago with my family and swimming out to sea with them. Once you've got a certain distance out, a pipe/line stops you going any further. The problem going further? You risk the chance of swimming into boats. I feel like I'm in a similar situation with my Personal Statement. My sister, Jennifer, and I reached a perfect equilibrium by balancing on top of the line - this way we could succeed at both crossing the line and also not getting chopped apart by boats at once. This is the metaphorical line I need to somehow reach.
As previously said, I have no problem just writing away, it's only when I have a purpose to write for I struggle. Given a topic specifically I am fine - it may take a few minutes and possibly a few drafts in order to write something worth reading but realistically I can be done pretty quickly.
I think that the character count also inhibits me when I'm writing a Personal Statement. I have little faith in UCAS patiently sitting there copying and pasting each applicaton into a character counter however obviously in order to appeal to them I should aim to stick under the limit (4000 characters if anyone was curious). 4000 also doesn't sound like a small number but for anyone who hasn't yet tried, squeezing the whole of your future ambitions and plans into 4000 characters is quite a task in itself. The fact that I'm also applying for Journalism makes it doubly difficult in my opinion as not only do I have to write a good Statement, I also have to write proving I can write whilst writing about my ambition to, in one sense, learn to write.
I guess anyone applying to university will struggle with their Personal Statement for the same reasons that I am; it's difficult not to show off, it's difficult to stick within the limit, and more importantly for me, it's difficult to stop blogging and start actually writing.