There’s tons of different kinds of bread, cheese, deli meat, spreads, nuts, fruit and vegetables that you can easily make a different combination every day for a while. And you could pack a lunchbox that is enough to feed you for the day and leave leftovers at home.
It’s nice when you’re wearing tight pants/ trousers. With a thong, there’s less chance of underwear bunching up and causing extra wrinkles and lines on the outer layer.