Spending someone else's money

Yeah, I know I've said that I wouldn't dabble into political issues much here, and I meant it. But I did reserve the right to do it every now and then. Well, today is now. Or then, take your pick.
I am a political conservative. Why? For many reasons, really, yet one does kind of stand out. I think we have to be very careful about taking other people's money and spending it however we like. The essence of government spending is exactly that: taking other people's money and spending it however we like.
I'm not arguing against any and all forms of taxing and spending. We need government, and government does need money in order to work. Still, the idea that something should have public money spent on it simply because I want it spent, because the majority of voters want it spent, that way, is hubris, even arrogance. No matter how good of an idea it might be on certain levels, and especially no matter how good of an idea you may think it is, it doesn't automatically follow that you should force other people to pay for it.
The simple guideline is that government should generally only spend for a substantial public interest. I would look at the 18 basic ways of public spending as outlined in Article 1 of the Constitution as a good guideline. After that, we really shouldn't be too quick to demand, yes, demand, that individuals cough up their cash for what someone else believes right and just. Simply put, that is the tyranny of the majority. That's as bad as the tyranny of a king.