Similarly, "Appearances can be deceiving." Nothing is as it seems usually refers to some form of deceptive illusion. It is usually in the context of some mystery or when some surprising truth comes to light. For example, in the movies when someone enters a quiet little town that seems strangely too perfect and everyone seems too friendly, and then night falls and bad things happen or they are collectively hiding something. Or, in a murder intrigue when the killer seems obvious but then someone realizes that something is wrong about it and in fact there is some kind of conspiracy. In a more real-life example, someone may discover learn their neighbour's family was abusive only after someone is killed; what appeared to be a wonderful family was quite dysfunctional.