Explaining "the Meta", Using Public Toilets as an Example

Originally, you may walk into a bathroom that has three stalls, and simply use the closest one. The rationale is that it is the most efficient use of your time; you don't have to walk as far.

One day you notice that everyone does the same thing; they take the nearest open stall. And you think about germs. You say to yourself, "I'm more likely to get some gross toilet-disease if I use the same stall everyone else is using."

So now, you always use the furthest stall, thinking it will give you the cleanest toilet. You share your discovery with your friends. They tell you they all do the same thing! Lo and behold, the furthest stall is actually the dirtiest, and the first stall is cleaner, because everyone perceives the first stall as dirty and the most commonly used. In fact, the second stall may be the cleanest, because people that really are in a hurry may be using the first stall, as well as those who mock the far-stall-using-meta-sheep.

As you can see from this illustration, the "rules of the game" influence the most optimal strategy. The restroom was built with three toilets, and one of them is the closest. This biases peoples' choices. But the meta is also itself influenced by the choices that people make, which is influenced itself by the choices of other players.

"The Meta" is the current state of the game that has resulted from all these factors. Something is off-meta if it doesn't fit into the way the game is currently played. But if something off-meta is found to be effective, and widely known, it then causes a meta shift, which is a response to this new effective thing.

Taking teleport on all five champions isn't meta, not because it couldn't work, but because people know how to play against it effectively. Sometimes people forget (or are new to the game and never knew) how to counter unusual strategies by exploiting their weaknesses. A five teleport strategy does have some significant strengths, but also some significant weaknesses. So your off-meta shenanigans will sometimes have hilariously successful results, as long as you play against bad players, or a major oversight is made in champ select.