When you discuss a topic and everyone agrees, the conversation often dies out quickly. But when you disagree, you're putting yourself in opposition to what was said and the discussion continues. Mahatma Gandhi said “honest disagreement is often a good sign of progress”, But are you good at disagreeing? Paul Graham, a computer programmer, proposed in 2008 a “Hierarchy of Disagreement” to rank the quality of disagreements from the least honest and effective, to the most complex and productive. Can you figure out which level you usually use?