So that you can make an informed decision. Also, there is often a middle ground. "Fat and salt are bad for me, so I will keep eating them, but now I will do it in moderation."

Similarly, there are times you may decide to take an action that will risk a lawsuit, but you can do so in an informed way by consulting a good lawyer. Paul Graham makes the point in http://www.paulgraham.com/softwarepatents.html that most startups should simply not worry about infringing patents. This is a calculated risk, but one they should know they are taking if they do so.

Similarly, there is a calculus of negligence (brief laymen's overview at http://en.wikipedia.org/wiki/Calculus_of_negligence ) that essentially says that if the probability of hurting someone else's property multiplied by the most likely damage is less than the cost to remove that risk, you simply accept the risk and be prepared to pay out the damage if it happens and do nothing to reduce that risk. This is a very calculated risk since if something happens you will be required to pay for it and the other party will rightly sue you if you do not. Yet the rational thing is still to just accept that risk, but you can only make that risk rationally if you have calculated that risk (perhaps with advie of a lawyer).

Maxwell Kennerly is an attorney, and thus defining his own role in legal consultations. I was at the doctor's office earlier today and made a decision about the costs and benefits of a medication which required considering the probability of side effects and the expense of purchase vs. the potential health benefits.

It's like asking a doctor, what are the health implications of eating ice cream daily? Then deciding it's worth it!