If you think any politician is going to give two shits about you because you "spoiled" your ballot, you are sadly mistaken. Decisions are made by those who show up. You're lucky enough to live in a democracy where you can vote someone to represent you at the highest levels of government. If you don't get involved and tell politicians what's important to you, and what you look for when you're voting, how can you possibly expect anyone to come along and pander to your views. If you wont get involved in your government, why should it get involved with you?