Produce Manager here. Place the end that opens directly between your two palms, and rub your palms together vigorously. The bag will stick to one palm or both, opening every time. Please stop licking your fingers to open these bags and then picking through our vegetables. You're gross.
Yeah, most people are aware of the process, though it doesn't make adding human saliva to the mix at the store level any more wholesome. There are a number of ways to open a plastic bag that don't involve your tongue.