2002: Angels win WS against the behemoth of a team assembled by SF, against all odds.
2003: Marlins are the worst team to make the playoffs, win WS over the much superior and heavily favored Yankees.
2006: Cardinals are the worst team to make the playoffs, make it crawling, beat arguably the best team in the NL (Mets) and a vastly superior Tigers squad en route to winning the WS.
2010: The Giants, who have a good team but are obviously inferior to the heavily favored Rangers, win the WS.
2011: The Cardinals, arguably the weakest team to make the playoffs in the NL, rolls to the playoffs en route to beat the absolutely best team in the playoffs, the Texas Rangers, to win the WS.
2012: The Giants, a good but flawed team proceed to beat the much much better and possibly best team in the playoffs, the Detroit Tigers, to win the WS.
The playoffs are a crapshoot. The way baseball works, anyone can win a short series. The only thing the better teams have in their is slightly better odds.