Why can I access the internet with all ports closed on firewall?

For the heck of it I wanted to see how much I could close down my router from the rest of the internet. I was hoping turning on the firewall, removing any port forwarding and turning off UPnP would make me unable to even browse the internet. However, my PS4 still had a connection when trying it out, also any internet browsing also worked.

What am I missing here? How can ports 80/443 be open for web traffic? Also, the PS4 that requires a bunch of ports to be open still worked. Is it because the request is coming from inside my LAN that it opens these ports temporarily?

Thank you.