U+1F60A · emoji since 2010
This gentle smile with happy eyes is pure warmth. It says I'm content, I'm grateful, or simply I'm being friendly, without any of the intensity of bigger grins.
It's a favorite for softening messages and closing notes kindly. A sentence that might read flat gets instantly warmer with 😊 at the end, which is why it shows up everywhere from texts to work chats.