Cafes in Ergani split into two camps: quick grab-and-go, and the kind where one cup buys you the whole afternoon. Where Black Cat 21 Cafe lands between those two, you'll know within the first five minutes — a book on the table, a backgammon board, or a laptop open all belong to the second camp; feet already pointed at the door belong to the first. Walk in and let the room tell you which one you're getting.