In Tokyo, the majority of people go to the "kombini" (convenience store) for lunch, buy food in plastic and styrofoam containers, then heat them in the microwav

In Tokyo, the majority of people go to the "kombini" (convenience store) for lunch, buy food in plastic and styrofoam containers, then heat them in the microwave. This is "normal" for Japanese. They won't be bothered by it. Unfortunately basically every tourist will be eating this stuff now.