A comment about the kind of post that regularly disobeys this rule:

I have found that putting the question to your local LessWrong meet up group is fun. An example: someone wanted to buy a car. We thought this was an interesting problem, so we helped him work on it. This involved roughly determining his utility function and actually calculating several options. Interesting solutions came up, such as renting an expensive, pleasurable car instead of purchasing a cost-effective but discomfiting car.