Well for instance like a Big Mac from McDonalds. It won't last forever, but if you buy one and you come home..you could stick it in the fridge(but I wouldn't leave it in there for more than a few hours at most) and once you take it out..maybe 20-25 seconds in the microwave will heat it up without messing with the taste or making the bread get all hard or any of that.
Heck for me when I get fast food I usually don't end up eating it right away I usually wait like 30 minutes since I usually like to have a toke first before I eat. Now I could have a toke and then go get the food but I don't want to be driving high if I can avoid it. Though for me since I only wait 30 minutes I don't put it in the fridge rather I keep it in the bag and I put it inside the microwave to keep warm and then once I'm ready I will heat it for maybe 15 seconds.
To be fair I've only done that with burgers or nuggets though.