It doesn't applies to every products (and it's probably different depending on which country you live in) but you also have to check if it's a "best before" or a "used by" date. I've ate dairy products 1-2 weeks after the "best before" date and they were exactly like the day I bought them. If it doesn't smell / looks funky it's usually fine to eat.
https://en.wikipedia.org/wiki/Expiration_date