What is the difference between 哈哈, 呵呵, 嘻嘻, and 嘿嘿? I always see 哈哈, 呵呵, 嘻嘻, and 嘿嘿 in WeChat, QQ, etc, but I don't really understand the subtle differences between them and when to use them appropriately, especially 呵呵. I use 呵呵 myself now, but I'm not sure I'm using it correctly.
check the table. This picture says everything.