Abstentions can be the most powerful vote, and with great power should come great responsibility. That's often not taught well enough in schools.
Abstentions can seem the laziest vote sometimes, but that doesn't diminish their power nor their responsibility. It is a freedom to be allowed to cast an abstention. Real democracy needs to allow for abstentions, especially explicit abstentions.
(In recent primaries there have been races where I have explicitly cast an abstention. No one will have read my "I don't care who wins this primary, I care who wins the general election" statements, but they are statements to be made. Right now some of the "strategy" in the US two-party system is one-party poisoning the primary vote of the other party by inflaming it with in-fighting in ways that leak into the general election. You have a harder time to win general elections when your candidate is already on fire coming out of the primary. "It doesn't matter who wins, let's stop in-fighting," is a message I can try to write on the ballot, even if not enough people hear it, it feels like the more powerful and responsible vote.)
The goal shouldn't be to get to 100% of people voting in every election, the goal should be to educate people that not voting is tacitly accepting the results of other people's votes. The goal should be teaching people that abstentions are a freedom, a right, a privilege, and should be treated as powerful and treated with responsibility.