When I was 18, the Pittsburgh Steelers were playing the Tennessee Titans in a playoff game. The game got to overtime and the Titans lined up for the game winning kick. Joe Nedney lined the kick up, hit it, saw it was going to miss, and took a dive in to the ground as a Steeler brushed his leg. A penalty was called, Nedney kicked it again, and after the game made some snide comment about being up for an Oscar. I put a hex on him after that incident and I kid you not, the guy blew his ACL out in the first game of the next season.
I briefly considered the power that I had been imbued with and just what kind of use I should put it to (I was leaning heavily towards "evil"), before I realized that was ridiculous. Curses are not real. They might feel real, especially after your favorite 97-win team continues their franchises 100-year streak of not winning a World Series, but I assure you, they are not real.
Manny Ramirez hit well during the postseason? CURSE! Alfonso Soriano disappeared during the playoffs? CURSE! A great regular season Lou Piniella team fell well short of expectations? CURSE! When you've existed for 100 years, sometimes bad things happen. Every franchise in baseball that's existed since 1908 has their own share of black cat and Bartman moments.
The Cubs haven't gotten a good break, but that's not entirely unusual. The Red Sox and White Sox both went almost 90 years without a World Series, the Indians are up to 60. Baseball is not known for it's historical parity, but eventually things even out. The last incarnation of the Dodgers had it right: "Wait 'til next year" is much better than "The Curse of the Billy Goat."