Our personal behaviour with and towards others tends to the Venn Diagram Principle. If two people are trying to decide what to do they tend to do what is in the shaded intersection area, what both will accept. This will be the least extreme or risky of the activities. When there are more than two people involved the shaded area gets smaller, less risky. We can see how this can make coalition governments unable to take radical action and why large groups of Italian tourists will always stand around blocking the exits to shops and tube stations. In government, consensus makes sense but in our private lives where we are looking for thrills one can see why things get boring pretty quickly and the attractions (perhaps only temporary) of someone who imposes him or herself and overrides the consensual position. Someone who acts from the unshaded zone. I suppose the solution should be for each member of a couple to take it in turns to dictate from what lies in their unshaded area, though this is tricky. Firstly, do I dare to tell you about my unshaded area, and secondly, if I do, it might put you off me forever. Thirdly, you might be so dull that you don’t have an unshaded area.