AITA for staying on my table in a resturant post paying the bill?

I went to meet a friend of mine for lunch today. The resturant we went to was something that our college group would frequently visit. And now after 6-7 years we were going back there, so there were some movies relived. Not sure if the information I gave will effect the story in anyway.

Now, we had our lunch and paid the bill as well. But while talking, the nostalgia tool over, and we stayed back at the table for 10 more minutes post the payi of the bill. My friend still had his drink with him, but it was a PET bottle, so it could be carried out. After 10 minutes, we got up to leave,just to hear a couple sitting behind us, call us assholes for occupying the table even after the bill was paid. I was surprised, since the resturant was as good as empty, multiple free tables around, and no guests waiting as well.

I did not pay heed to it at that time, and we just left the establishment, but post that, my mind has been wondering if we were the AHs to actually occupy a table after paying the bill.