PULL

See that? That’s a sticker on that glass door you’re about to open. It says PULL. But here’s the thing, the sticker is on the other side of the door. It’s an instruction on opening the door, but it’s not for you. For your eyes it’s backwards, like a mirrored version of the word, but your brain still reads the word PULL.

There’s no other sticker that says PUSH for you. Sometimes they don’t bother with that because they only want to notify the people who need to pull the door.

But it’s too late, your brain has read the word PULL and processed the instruction, at the same time, your brain is processing that the word is on the other side of the door and so it’s not to be done on this side of the door and so you probably need to push. Of course this bit of processing takes longer and the PULL request has kicked in much quicker. You pull the door, it doesn’t open, then you push and succeed in opening it.