Well I save a lot of leftovers, but I don't think to the extreme you all are talking about. 3 tortillas is very much "food" in our house as it's good for quesadillas, but if you meant tortilla chips--well those would go in my mouth before throwing away the bag. Same with 3 berries
I have a friend who saves NOTHING and throws away all leftover. It drives me crazy, but apparently I drive her crazy for saving things that, yes, someone will end up eating. I'm a decent cook and can repurpose a lot into a meal. Ie a stir fry from leftover vegetables from a few different nights and leftover chicken breast when we are all the dark meat for dinner the night before. Add rice and sauces and maybe a scrambled egg and you have a lovely meal.
I grew up poor, my friend did not. I assume this could be part of the difference?