What is red hat thinking?

It's to do with a group thinking tool called the six hat method that was developed by Edward De Bono. A red hat is for Emotions and Feelings. So Red Hat Thinking implies that you are reacting with your emotions rather than looking at the facts (which is a white hat, by tyhe way) However you are supposed to wear all hats during the discussion to look at the problem and solution from all angles, so wearing a red hat thinking is part of the process, not a issue in itself.