Cross chaining

I've had my GIant Trance 2 for almost a year now and I love it, its perfect for the Dam and also went beautifully down at Stromlo, Sparrow and Madura a while ago. Probably ride 2 -4 times a week, depending on work and weather so it gets a good going. Anyhow, I'm not too mechanically minded, but did notice the gears cross chaining under a bit of pressure, eg going up the pinches or half way up a hill, so took it to the shop to get checked. Found that the gear cables where they come out under the frame were worn away and then there was not enough pressure in the cables and that was causing the slipping. Anyhow, all good now and it needed a service anyhow.