I forget who originally wrote something like this (ripping off from unknown source), but it always stuck with me. Imagine it's 2001. George Bush has just been selected by the Supreme Court. You really don't like George Bush. Then some guy claiming to be from the future shows up and tells you that George Bush is going to fuck things up so badly that the next president is going to be a black Democrat named Barack Hussein Obama. You probably don't believe him.
...ah, Tom Tomorrow.