So what do you do, when the units you've bought add up to 170cms wide, but because the wall was uneven you had to build out the tiles so the room is not longer 175cm wide, but is 169.5cm instead? You commit the biggest act of lunacy ever and spend the afternoon scribing the tiles to accommodate the units, while praying that you don't crack a tile, and covering everything in more white dust than a weekend at Liam Gallagher's. All for the sake of 5mm. This is why I look so glum 90% of the time.