The inconsiderate asshole who is to be blamed for everything that goes wrong in your life.
Example 1

I wanted to fry up some eggs and bacon for breakfast today, but Yesterday Me decided to eat the hole goddamn fridge empty.

Example 2
Guy 1: You know that psycho chick i finally got rid of a couple weeks ago?
Guy 2: Yeah?
Guy 1: Well Yesterday Me thought it'd be a laugh to call her up and go sleep with her. Now i'm stuck with her. Again!
Guy 2: Man, i really hate that guy!
by B0hem May 18, 2010
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