My mum has always made a weekly meal plan for as long as I can remember. So for me it seems pretty normal. However, because I'm a student and cook for just myself, I only need three 'meals' and just use the rest as leftovers. I'm a bit of an erratic eater though, and find it hard to judge the quantity of food I'll need. No food seems to go to waste though. (scraping perfectly good food into the bin should be a crime)
I have tried online shopping before, but I hated the hassle with the site always freezing, the number of plastic bags they used when the food arrived, and some of the produce wasn't always amazing..
So yeah, I do pick up food I wouldn't have normally, but I'm happy to spend that little extra treating myself on some reduced blueberries or maybe a nice dessert. And if I pick up half price meat/poultry I can just use it in next week's meal plan.