I love stores with self checkout. One reason is that I can pack my shopping bags the way I want - usually I separate things by where they will go when I get home. Then there's the fact that no one looks at you funny when you buy diet soda and cookies. But mostly because I can usually scan, pay and bag quicker than lots of the help at the store.
So shop, scan and don't be embarrassed by those M& M's and diet Coke!