Sudoku madness

I appear to have a minor Sudoku obsession. I bought a book of them to do on the train to and from my holiday and only completed about half of them, and now I find myself working through the rest every evening in a slightly concerning manner. I'm onto the hard ones now and it appears that the more I try to do, the faster I try to do them which inevitably means I get it wrong at some point without noticing and it all goes tits-up. Tonight I tried one of the giant 4x4 ones and after over an hour of really careful thought (see? Deeply scary!) I found it didn't work, but I had no idea where the mistake was. My book is now littered with little phrases that I uttered at the point when I found mistakes, and then felt compelled to write down. These include "Bugger", "Sodding bollocks" and "Arse", while the giant one is now titled "So bloody annoying". I worry myself sometimes. I think I may be turning irrevocably into someone who lives alone and talks to themselves and does Sudoku. Next thing you know I'll have 7 cats and then it's only a matter of time until children won't go past the house because they're frightened of the Mad Cat Woman with the crazy hair (although my hair is actually looking really good this week) who has walls covered in little grids of numbers.

Ok, so I didn't entirely mean all of that last bit, but I feel the Sudoku obsession ought to stop. Maybe tomorrow I'll buy the Guardian and do the Kakuro instead...Mwahahahaha.