Aisha (radi Allahu anha) narrated that the Prophet (sal Allahu alaihi wa sallam) entered upon her one day and saw a small piece of bread on the floor, so he picked it up and wiped it, then told her: “O Aishah, treat the blessings of Allah with respect, for when it departs from a household it may never come back to them.”
Seeing a small piece of bread on the floor made the Prophet (sal Allahu alaihi wa sallam) warn Aishah regarding being ungrateful to Allah (subhana wa ta’ala). What would he have said were he to see how plates full of food are thrown away in dustbins? Parents take their children to others’ houses, put food on their plates and say nothing to them when they remorselessly leave it to be thrown away.
These are the very same people who you will undoubtedly see complain about not having enough.