When talking to some one, whether it be in person, e-mail, or IM, and it feels like your talking to yourself, like all of your words are just bouncing off of a brick wall, and never reach their ears/eyes.
Brick Wall Effect in action:
Guy: I love you so much babe...
Girl: *While texting* Thats nice.
Guy: Babe?
Girl: *still texting* How do you spell Wednesday?
9👍 3👎