Nah, take as much time as possible, and also always avoid the self-checkout. Don't play along with these corporations trying to eliminate jobs, give the cashiers job security by asking lots of questions and taking your sweet ass time at the register. If you have to do self-checkout because there's no open cashiers, always ask for assistance from the nearest attendant.
Oh god no. I am a cashier, and trust me we are not paid enough to deal with that bullshit. Just lemme scan your shit, pay for it all, and then go! We have stuff to do other than helping customers and don't need to be playing counselor or customer service clerk for someone who just is trying to take up our time.
You are not helping. You are not giving us job security. All you're doing is causing us undue stress.