I don’t think you understand how ranked voting, or instant-runoff voting works. No vote of yours would be “tossed” to someone you didn’t vote for.
Let’s say your ballot has six candidates on it for president. Trump (Republican), Clinton (Democratic), Johnson (Libertarian), Stein (Green), Castle (Constitution), and Estela La Riva (Socialism and Liberation).
Now, let’s say that Voter A likes Jill Stein better than anyone else on the ballot. He votes for Stein as his first choice. For his second choice, he picks Clinton. What the second choice is basically saying is, “if Stein isn’t in the top two, I pick Clinton.”
Voter B is a bit more conservative, and he likes Gary Johnson. So Johnson is his first choice. However, he can’t stand Trump, so his second choice is Darrell Lane Castle of the Constitution Party.
Now voting is over and all the ballots are tallied. Trump and Clinton are the top two vote getters in the first-choice voting in this state. Now, all the ballots that didn’t choose either Trump or Clinton as a first choice are reconsidered for second choices, and this includes both our Voter A and Voter B, as neither one of them voted for Trump or Clinton as a first choice. In this second wave, anybody who voted for Trump or Clinton as a second choice will have their vote count for that candidate. For example, Voter A picked Clinton as a second choice, so that’s another vote for Clinton. Anyone who didn’t pick one of the top two as a second choice will not be counted for either candidate. As Voter B chose the Constitution Party candidate for his second choice, his vote won’t be applied to either Clinton or Trump. See how that works?
The advantage to this kind of voting is that voters can vote for their favorite candidate, regardless of party, without feeling like they’re throwing their vote away. Minor parties will then get more support and a bigger profile — and this means that eventually, their candidates may even be in the top two someday.