I read a note on a popular site tonight while watching the games: "Over the past 3 years (also known as 'since the Nats became relevant'), the Braves have a 28-19 record against Washington. The Braves should be aiming for nothing short of a sweep."
This is completely useless as an indicator of what may happen going forward. On April 13, 2013, the Braves beat the Nationals 3-1. Tim Hudson got the win; Eric O'Flaherty pitched a scoreless eighth inning for Atlanta. Tim Hudson now pitches for the Giants; O'Flaherty is a member of the Athletics. That Braves team has vanished and no longer exists.
The August, 2014 versions of the Nationals and Braves have never met before this month. Rosters are turning over constantly. Even if the clubs seem similar and the names are familiar, the players in the uniforms are brand-new versions of themselves. This year's rendition of Evan Gattis wears shin guards and is markedly superior to last season's batter. Doug Fister looks sharp in red and white.
It's a mistake in judgment to use a game from three months ago as a predictor, let alone three years. When I read something like I did tonight, I giggle and look for someone to complain to. Congratulations! You are that person.