You are never going to agree with EVERY policy that a political party puts forward or implements when they're in power. However, so long as you agree with what the party TRULY stands for then you're vote is not wasted.
The trouble is, sussing out what the main political parties TRULY stand for is a bit harder to ascertain than some of the smaller parties.
You're right there. And for me that's the key problem, I don't really know who truly stands for what at the moment. I'll never agree on every policy but there are times when I struggle to agree on any!