Is this actually what she was writing all this time? That's a bit ridiculous if you think about it.
Every Monday morning, she'd need to read her diary to be able to 'remember' her friends. There's two flaws with this:
1. Most of the stuff she wrote was a bit long and pointless, with every entry taking up at least a page. As time goes on, she'd have to read more and more pages. Think realistically: She's reading this before she goes to school. With all these pages it's going to take quite awhile. Most of the people I know don't have an awful lot of time
in the morning, so how does she manage to read all of that, along with the normal morning routine?
2. Going along with the increasingly large amount of pages that need to be read, how in the world is she supposed to have that all memorized? The thought of being able to read that many pages and remember it all sounds impossible. The idea of eventually remembering something specific that reoccurs constantly is reasonable, but remembering everything in her diary just from one read just sounds stupid.
Then again, the fact that I'm making a conspiracy theory about Isshuukan Friends only shows how horribly my life has spiraled downward..