Mine is that I don't support many seemingly innocent charitable causes. I'll give you three examples: cancer research, post-hurricane rebuilding, and faith based initiatives.
By asking for donations for cancer research, we are claiming that the price system is not sufficient. There are surely huge financial incentives to cure cancer (which I am told is a broad word for several different kinds of diseases). Even curing one kind of cancer would be extremely profitable. The market should be able to predict exactly how profitable, and put that much money into research every year. But remember, profit isn't the extra money greedy CEO's use to torture kittens. But they are an exact value that consumers place on a product. If you put more money into research than would come out in value, then you have done a disservice. That money could have been better spend elsewhere. Is there a valid reason to think that the market is undervaluing a cancer cure?
Another example is the large amount of resources being donated to help rebuild areas like New Orleans after huge hurricanes like Katrina. When money is given to these area, we are only subsidizing people to live dangerously below sea level. Why not do the same for houses near volcanoes or earthquakes (wait, we do that second one). That money would be better spent subsidizing their move to other, safer, parts of the country.
Barack Obama has stated that he favors these faith based initiatives. Here are his statements: "but they can also participate in federal programs as long as those are done in a way that is not encroaching on a separation of church and state, is open to the public and is not involved in proselytizing." I don't trust the government to produce many things, especially my religion. I strongly support the separation of church of state, for the benefit of the state and the church. A Christian charity that does not also preach the gospel of grace is hardly a Christian charity at all.
Now that I've confessed, what is your most controversial belief?