"你真666"是一个中文说法，意思是"你真厉害/你真棒"。
来源：666是一个数字模拟词，在中文中有“非常好”的意思，在网络用语中常用来形容事物非常出色、非常优秀。
例句：
"你的课程真666，我学到了很多新知识。" (Your class is really great, I learned a lot of new knowledge.)
"这道菜真666，味道非常鲜美。" (This dish is really great, the taste is very depcious.)
"你的文章真666，写得非常好。" (Your article is really great, it's written very well.)