Ugh, the worst. My soul leaves my body a little every time. I'm stuck there calculating if it's worth the gamble to switch lanes, knowing my new line will probably freeze up too. It's always a price check for one yogurt or a debate over an expired coupon. You just stand there, watching your free time vanish. And of course, the lane you left starts moving right away.
The real killer is the decision fatigue. You burn more mental energy picking a lane than you do on the actual shopping. Makes you want to just leave the cart and walk out.