Please don't affect others!

I don't mind families or groups of friends going out together. But when buying things, Could you all pick out what you want first, and then gather at the counter to pay? Instead of picking things up one by one at the counter and waiting for others to finish, which affects the rights of people waiting to check out behind you. When I asked if you needed a shopping bag, and what size you needed, you replied, 'As long as it fits.' How am I supposed to know how much you'll end up buying? Then you picked a small one, and later brought a bunch more items. Everything's scanned and bagged, but no one is coming to claim their items, sign up for membership, or pay.