FWIW, I used to feel the same. I voted my conscience, even when that meant voting third party or not-on-the-ballot write-ins.

Then we had Bush v Gore, when I had voted Nader. I got to see (In my opinion) a lot of bad decisions, and a lot of Constitutional violations. I felt responsible. (Was it my vote that made the difference? No. That doesn't make me feel better, because it was the concept that I backed that let this happen).

So now I vote for someone I can accept. I still value anyone that votes their conscience, as as I've argued above voting at all, even a "wasted" vote, is more meaningful than not voting. But I myself feel responsible for too much to do it when the stakes are high.

I'm not addressing not voting when you don't understand/know the issues - that's a separate discussion.