Why are people so pionate about politics when both parties are the same?

Both believe in deficit spending, both believe in big government, etc. There hasn't been much change in the past 30 years since Carter's presidency. The only real difference btw the two parties is the Dems believe in deficit spending to feed people and the GOP believes in deficit spending to kill people. Other than that they are the same. The healthcare bill that is so lambasted across the nation was proposed and implemented by a Republican first and then subsequently copied by a Democrat.