How to Give Non-Optimally

In 2011, Pama became a member of Giving What We Can. And that involves taking a pledge to give 10% of your lifetime income. Do you ever give non optimally? Well, I guess I don't normally give to what I would count as ineffective charities. But that's not because I regard every instance of doing so as wrong. It's more because I just don't have a lot of money to give away.