Wake Up
While you may be upset at the fact that the zombies keep winning over whatever you're voting, it doesn't change the fact that you're one survivor in a pack of flesh-eating zombies and the flesh-eating zombies are going to do what flesh-eating zombies do. Whatever they want.
You may not like your choices, but you have them. Throwing your choices away is, again, your choice. Honestly, I believe voting third party to be worse than throwing away a choice. Instead of chosing the lesser evil of a candidate that may win, you've chosen futility. You vote with the same thought in mind as the people who don't vote at all, so they can say, "Well, they weren't my president, I didn't vote for them."
By the way, we aren't "most countries". Welcome to the US. We have what is essentially a two party system with third party runners that like to spend their money removing votes from either of the two parties that will actually end up in office. For instance, third party runners like Perot managed to get Republicans in office. Again.
Voting third party, as unhappy as it make you feel, is essentially throwing away your vote, which is my answer to one of the questions you originally posed.
I can say that my candidate has a chance to become president. Looking at the voting habits of the past and the current pole demographics, can you?