You can't "waste" a vote. A vote is a calling of your choice for who you think it the better candidate. It's not like rollover minutes, where you get to keep your votes if you don't use them. They go away if you don't use it, so you can't waste a vote. The only way to waste a vote is to vote uneducated. It is your duty to not only vote but to make an educated vote that is to the best of your ability. If you don't like the candidates, suck it up and maybe you should register in a party so you can vote in the primaries. Then you have a say in who's the candidate.
Your argument of wasting a vote is ridiculous because it's not like you get to keep it if you don't feel like using it on someone who's sub par