yeah it depends on what it is. If it' something that spoils easily like milk hell no. If it's a day or two after the date and it's something like chips then maybe.
Not usually, but a few things like sweet stuff don't usually go off for a while afterwards so they're usually fine. I have a bad habit of throwing milk away a day or two before it goes off though.
Yes. In most cases the expiration date is just orientative. Y'all would be surprised of the amounts of good food that is thrown away because of expiration dates.