Well, it's somewhat hidden in steps 2 and 3. You have to be able to correctly state your hypothesis and to indentify all the possible variables. Consider chocolate water: your hipothesis is "There exist some brands of water that tastes like chocolate candy". Let's say for whatever reson you start with a prior probability p for this hypothesis. You then try some brands, find that none tastes like chocolate candy, and should therefore apply bayes and emerge with a lower posterior. What's much more effective, though, is evaluating the evidence you already have that induced you to believe the original hypothesis. What made you think that water could taste like chocolate? A friend told you? Did it appear in the news? In the more concrete cases:

• Sex partners : Why did you expect them to be able to satisfy you without your input? What is your source? Porn movies?
• Computer repair shops : Why did you expect people to work for free?
• Diets : Have you talked to a professional? Gathered massive anedoctale evidence?