Several things. You begin addressing random black cats as Yoruichi, You come up with unique names for various melee combat fight moves(don't know what to call that part exactly), You begin spouting random japanese that you have started to pick up, and most of all none of the previous bothers you in any way shape or form. =P
What happens... you don't sleep for nights on end and start ditching class all the time, and never join sports teams, even though they'd love to have you, and yet your grades stay straight As and you don't get fat even though you can't prepare good meals because you're too busy watching anime. O.o
If you watch a lot, you get addicted to it but you also start seeing everything somehow related to anime or you use anime references IRL or start merging Japanese into everyday speech. Unless you already speak Japanese....
Its like when you want to open your 3rd eye by meditating daily. Anime is a way of opening my mind to different universes. These dream worlds where not only while watching anime, but on the bus home or to work, everywhere I go I dream of being in an alternate world. The more anime I watch, the more my imagination expands.
And also my wife gets mad, says I dont pay attention to her. So I have to leave off where I am.