No one vote counts, but the overall numbers do matter (at least in functioning democracies).

If your preferred party gets in, great, your vote almost directly counted.

If the party you disliked gets in, sad, but your vote still sends a message that the winner that they have alienating you any the others who didn’t vote for them. If they keep doing that to more voters, they risk losing the next election.

(Again, all requires a functional democracy)